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THE BOYS' OWN BOOK OF GREAT 
INVENTIONS 



THE MACMILLAN COMPANY 

NEW YORK • BOSTON • CHICAGO • DALLAS 
ATLANTA • SAN FBIANCISCO 

MACMILLAN & CO., Limited 

LONDON • BOMBAY • CALCUTTA 
MELBOURNE 

THE MACMILLAN CO. OF CANADA, Ltd. 

TORONTO 



DEC -6 IS18 




Thomas A. Edison, America's greatest inventor. 



THE BOYS' OWN BOOK OF 
GREAT INVENTIONS 



BY 

FLOYD L. DARROW 

HEAD OF SCIENCE DEPARTMENT 
POLYTECHNIC PREPARATORY COUNTRY DAY SCHOOL 



ILLUSTRATED 



N?m fork 
THE MACMILLAN COMPANY 

1918 

All rights reserved 



^3 



Copyright, 1918 

By the MACMILLAN COMPANY 

Set up and electrotyped. Published November, 1918. 



CI.A508404 



-' \ 



PREFACE 

The purpose of this book is to tell the story of some few 
of the great epoch-making inventions, to trace their in- 
fluence upon world progress and to describe, so far as pos- 
sible, simple experiments, embodying the principles in- 
volved, for home laboratory work. Many very important 
inventions and discoveries have had to be omitted. The 
field to be covered is so broad and the limits of a single book 
so narrow that the selection of subject-matter has been of 
necessity largely a process of judicious elimination. But 
in a book of this sort it is not so important what particular 
subjects are discussed as it is to teach certain fundamental 
truths and to emphasize the tremendous influence upon 
human affairs of the so-called dreamer, the man of vision, 
who in spite of every obstacle of fate and man has blazed 
the path of progress for the race. We cannot point out 
too often that genius is very frequently but another name 
for imagination. The inventor and the poet are in spirit 
one. The poet creates a mental image and clothes it in 
words suggestive of the thought picture. The inventor 
conceives the idea of an instrument, fraught with great 
material possibihties, and embodies it in a suitable mechan- 
ism. Both the poem and the machine, as everything else 
in the universe, are mental creations. The most intricate 
piece of machinery existed in the mind of the inventor 
before it could be translated into visible and tangible form. 
But in every instance the thinking of the inventor must 
be true to the eternal laws of the universe if bis creation is 



vi Preface 

to have meaning and purpose in it. The inventor's roincl 
is a mirror of universal truths and if his thinking does not 
reflect them as they are, the product is distortion, error and 
failure. Some few great minds have caught the vision of 
a small portion of the truths of Nature and have ma- 
terialized them for the benefit of mankind. But there 
is still an ocean of almost infinite possibility for the inventor. 
The age of discovery and achievement has only just begun 
and we may be perfectly sure that, so long as the race is 
here, there will yet be progress to make. Surely the mir- 
acles of Science have not all been wrought. 

The writer is under obligation to a large number of busi- 
ness organizations for their kindness in supplying photo- 
graphs and material used in the preparation of the book. 
He wishes especially to acknowledge his indebtedness to 
his wife for making more than two-thirds of the drawings 
for the line cuts and for typing the manuscript. Credit 
is also due to Miss Beatrice Booraem for a part of the 
drawings used in the cuts. 

Floyd L. Darrow. 
Brooklyn, N. Y., 

August 15, 1918. 



CONTENTS 

PAGE 

Preface v 

Chapter 

I. The Gyro Paradox i 

n. The Telegraph 25 

m. The Telephone Romance 40 

rv. Principles of the Telephone 61 

V. The Triumph of Wireless 72 

VI. The Theory and Practice of Wireless 92 

Vn. Talking through the Ether 1 24 

VrH. The Story of Aviation 134 

IX. The Principles of the Aeroplane 156 

X. "The Assassin of the Sea" 173 

XI. The Story of the Steam Age 194 

Xn. Solving the Small Power Problem 212 

Xni. A Century of Agricultural Progress 232 

Xrv. Two Centuries of Electricity 244 

XV. The Evolution of Artificial Illumination 299 

XVI. Fire and High Temperatures 309 

XVn. Some Notable Achievements m Chemistry 326 

XVni. The Story of Iron and Steel 348 

XIX. Galileo and the Telescope 367 



vu 



LIST OF PLATES 



Thomas A. Edison Frontispiece 

Facing Page 

Speeding up the gyroscope 4 

Precessional movement of the gyroscope 5 

Applications of the gyroscope 8 ■ 

Thomas A. Edison and Henry Ford at the Panama Exposition 31 

Early telephone instrmnents 46 • 

Opening transcontinental telephone service 57 

Naval and military wdreless stations 89 

Amateur wireless laboratories 90 

Wireless apparatus 117 

Telephoning across the continent by wireless 130 

Wright biplane and Zeppelin 143 

Hydroplane dropping depth bomb on a submarine 151 

A torpedo and sectional view of a submarine 187 

Steam turbine and generator 205 ' 

Locomotives 208 

Gasoline and gas engines 225 

First Haynes automobile and first Stanley Steamer 227 

From the hand cradle to the harvester-reaper and thresher 236 

The farm tractor and the portable electric motor 238 

An Edison power and electric light plant 239 

Electrolytic refining of copper and electro-magnet 266 

Edison storage cell 274 

Electric dynamos and motors 287 

The Ford Power Plant 293 

Electric locomotive and Niagara Power Plant 296 

Laboratory in which Edison made the first electric lamp 302 

Types of electric lamps 303 

Oxy-acetylene, thermit and electric welding 316 

A boy's chemical laboratorj'- and a dynamite explosion 2>Zi 

Modem coke ovens and by-product plants 339 

Stages in the manufacture of steel 356 

World's largest reflecting telescope 373 

ix 



THE BOYS^ OWN BOOK OF GREAT 
INVENTIONS 



THE BOYS' OWN BOOK OF GREAT 
INVENTIOiNS 

Chapter I 

THE GYRO PARADOX 

We are all acquainted with the spinning top vender who, 
on the crowded street corner, at the automobile show or 
country fair, displays his wares and demonstrates to a 
curious and credulous group how his uncanny gyros utterly 
defy the law of gravity, and tells you that no scientist wise 
enough to explain their action has yet appeared. 

But gyroscopic action is as old as the universe itself 
Do you know that the earth beneath your feet is a huge 
gyroscope ceaselessly obeying the same laws as the spinning 
top? The rolling hoop which as a child led you many a 
merry chase owes its balancing power to these self-same 
laws. At once the plaything of children and the marvel 
of sages, who of us Kttle more than a decade ago would 
have imagined that within this toy lay hidden the possibil- 
ities of the mono-rail car, a gyro-compass of absolute re- 
liability and infinitely more accurate than the magnetic, 
an automatic aeroplane stabilizer, a means of steadying 
a ship in the roughest sea, a steering device for the torpedo 
and perfect proof of the earth's rotation? Do you realize 
that the wonderful stability of your wheel or motorcycle is 
due solely to the principle of the spinning top and that it is 
the gyroscopic action of a swiftly rotating bullet that carries 



2 The Boys^ Own Book of Great Inventions 

it straight to the mark? Do you know, too, that the pole 
star of to-day is not the pole star of ten thousand years ago 
nor will it continue to be the pole star of the future? And 
this because of the gyroscopic movement of the earth as it 
spins on its axis and at the same time whirls about the sun. 
Far from being a puzzle the gyroscope admits of both 
mathematical and popular explanation. Its marvelous 
balancing power is one of the most striking illustrations of 
the fundamental law of inertia, the most common property 
of all matter. Inertia means inactivity. A body at rest 
tends to remain at rest or if in motion to continue in mo- 
tion unless acted upon by an outside force. This is a matter 
of common experience. As we endeavor to keep our bal- 
ance in a swiftly moving subway train with its sudden 
changes of motion and bending about sharp curves, we get 
a very vivid realization of the opposition which a body offers 
to any change in its state of rest or motion. The distance 
to which the athlete throws the discus is determined by the 
quantity of inertia which he can store up in it as he whirls the 
circular plate about his head. When he throws it, too, he 
simply lets go and the inertia of the moving discus carries 
it off in a straight line tangent to the curve in which it 
moves. The inertia stored up in a massive flywheel keeps 
the machinery running smoothly and without vibration. 
A moving train does not stop when the power is turned off 
but only when the brakes have been appHed and the fric- 
tion and air resistance have overcome its momentum, and 
momentum is simply the inertia of a moving body. The 
earth rotates on its axis and revolves around the sun with 
no change in its velocity because it meets with no resistance 
and is itself powerless to accelerate or retard its motion. 
Its inertia keeps it going. So with our top, or gyroscope. 
When set spinning it resists with a force, altogether greater 



The Gyro Paradox 3 

than would be expected from its size and weight, any 
tendency to change its plane of rotation, or the direction 
in which its axis points. This is simply the inertia of a 
rotating body and its magnitude depends upon the mass 
and speed of the body. The swiftly turning wheels of a 
motorcycle resist with a tremendous force any change in 
their plane of rotation and therefore balance themselves 
and rider in perfect security. 

To better study the laws of rotating bodies I made a 
gyroscope from a bicycle wheel and operated it with an 
electric motor. On one side of the hub I brazed a clutch 
similar to that of an automobile crank. I extended the 
cone shaft about two and one-haK feet by boring and thread- 
ing a hole in the end of a steel rod and screwing this onto 
the projecting end of the shaft. This was made secure with 
a set-screw. About midway of the bar a socket was bored 
to provide for mounting the spinning wheel upon the up- 
right support. A chuck and holder to fit the end of the 
motor shaft were provided so as to engage the clutch in 
speeding up the gyroscope. I weighted the rim with a 
large number of turns of copper wire, holding it in place 
with copper bands, and trued the wheel about the shaft 
perfectly with small quantities of solder placed wherever 
needed on the rim. The heavier the rim the less will be 
the speed required, but a fellow experimenter in using lead 
for this purpose found that as he speeded up the wheel the 
lead began to leave the rim and he very prudently began to 
leave the room. 

In making a demonstration the operator holds the clutch 
of the gyroscope firmly against the chuck on the end of the 
motor shaft and his assistant gradually speeds up the motor. 
When a fairly high speed has been attained the gyroscope 
is withdrawn and mounted upon the support as shown in 



4 The Boys' Own Book of Great Inventions 

the cut. Instead of falling, however, the end of the shaft 
bearing the wheel stands slightly above the horizontal and 
the gyroscope at once begins to revolve, or ''precess" about 
the vertical support, seeming to the popular mind com- 
pletely to defy the law of gravity. As the speed of the 
wheel dies down its axis slowly drops to the horizontal, 
then below and gradually the action ceases. If the wheel 
be operated in the opposite direction the same phenomenon 
occurs except that the precession is also in the opposite 
direction. Holding the rapidly rotating gyroscope in the 
hands one experiences no difhculty in moving it in any 
direction so long as the plane of rotation is not changed. 
But attempt to disturb this and a tremendous resistance at 
once develops. One seemingly wrestles with a giant. We 
are opposing the inertia of a rotating body and find that it 
is very great. Once set spinning in a certain plane our 
gyroscope continues to rotate in that plane with all the 
momentum it possesses. 

But why does the gyroscope precess? Why does it not 
fall? Far from being in defiance of the law of gravity it is 
on the contrary because of this law that the gyroscope be- 
haves as it does. A body that is under the influence of two 
forces or two motions at the same time can never act as 
though it were under the influence of only one. And this is 
just what the popular mind does not take into account. 
Our gyroscope is made to rotate about one axis and it will 
be readily apparent that the gravitation of the earth tends 
to rotate it about another axis at right angles to the first. 
Therefore the gyroscope can rotate about neither axis as 
though the other rotation were absent, but must tend to 
rotate about an axis lying between the two. In trying to 
place itself parallel with this intermediate axis the gyroscope 
begins to revolve, or precess as it is called, but in so doing 




Speeding up the gyroscope. 




Demonstrating the precessional movement of the gyroscope. 



The Gyro Paradox 




•:^ 



the direction of each axis shifts, and so long as the speed of 
the gyroscope keeps up its own axis will continually chase 
this intermediate axis about the vertical support but never 
catch up with it. Were there 
no gravitational force our gyro- 
scope would rotate with its axis 
at right angles to the support 
but there would be no preces- 
sion. This is conclusively shown 
by placing a counterpoise on 
the free arm of the gyroscope 

shaft just sufficient to balance Fig. i.— In the above diagram the 

the weight of the wheel when 
the precession immediately 
ceases. Thus when the force of 
gravity is neutralized the gyro- 
scopic action disappears. If 
the counterpoise is moved to 
the end of the shaft causing 
the wheel to move upward, 
precession at once begins again 
but is in the opposite direction. 
After such a demonstration 
even the most skeptical could 
never assert that the gyro- 
scope suspends the law of 
gravity. 
The earth itself affords one of 



wheel is rotating about axis 
AB and at the same time the 
force of gravity is tending to 
pull it downward along arc 
BE and about axis AD. 
Therefore the wheel being 
under the influence of two 
curvilinear motions tends to 
move forward so that its axis 
of rotation will coincide with 
the intermediate axis AC 
and in so doing begins to 
"precess." As the wheel 
precesses, however, both axes 
AB and AD also move for- 
ward and with them axis AC 
thus causing the precessional 
movement to continue so 
long as the wheel continues 
to rotate. 



the most perfect examples of 
gyroscopic action. Because of the earth's constant rotation 
its axis with slight variation points in the same direction 
from century to century. It is simply a spinning top. At 
the same time that it rotates on its axis, however, it is re- 



6 The Boys^ Ow}i Book of Great Inventions 

volving around another axis in its annual movement about 
the sun. The two axes are inclined at an angle of 23 3^ de- 
grees to each other and therefore just as our gyroscope 
precesses so does the earth. It is continually endeavoring 
to place its axis parallel to the axis of its orbit but with 
no better success than the gyroscope. But the precessional 
movement which results, constantly shifts westward the 
equinotial points, where the sun crosses the equator, at the 
rate of 55 seconds of arc each year and causes the axis of 
the earth to describe a small circle in the heavens com- 
pleting it once each cycle of 25,900 years. In other words 
the earth wobbles just as a top does in dying down. This 
accounts for the former statement that the pole star is not 
constant. 

One of the more recent and probably the most important 
appHcation of the gyroscope is in the gyro-compass. This 
compass is now a part of the equipment of all modern 
battleships and submarines in the various navies of the 
world and it is a matter of no Httle pride to Americans that 
an American inventor, Mr. Ehner A. Sperry of Brooklyn, 
has contributed most toward the perfection of this mar- 
velous piece of mechanism. 

In order to understand the action of the gyro-compass 
suppose we carry a gyroscope, mounted similarly to the 
one shown in the cut, to the North Pole. Such a gyroscope 
has three degrees of freedom, that is, it rotates upon one 
axis and is free to turn about two others, one horizontal 
and at right angles to the first and the other vertical. 
Suppose now that we clamp the gyroscope in a horizontal 
plane allowing it to turn only about the vertical axis and 
then set it spinning. If by means of electricity we keep 
up the spin the axis of the gyroscope will point constantly 
in the same direction but. because of the rotation of the 



The Gyro Paradox 




earth beneath it, this axis will seem to turn successively to 
every point of the compass and describe a complete circle 
every twenty-four hours. Thus 
does the gyroscope prove the 
earth's rotation. 

Now suppose we make a larger 
and heavier gyroscope mounted 
with three degrees of freedom 
and operated by electricity. Let 
us as before clamp the gyroscope 
in a horizontal plane but give it 
freedom about the vertical axis 
and then set it spinning. Now 
since the gyroscope is under the 
influence of two motions, its own 
rotation and the rotation of the 
earth, it is bound to precess just 
as our bicycle wheel did and will 
slowly swing around until it has 
placed its axis in line with the meridian, or in other 
words pointing true north and south. It has done as far 
as possible what the gyroscope is perpetually trying to do — 
place its axis parallel with that of the larger curve in which 
it is moving. Now let us unclamp the horizontal ring giving 
the gyroscope freedom to move in a vertical plane and 
slowly its axis will rise until it is parallel with the axis 
of the earth and points to the pole star. And there it will 
remain pointing, not to the magnetic north but to the true 
north, with an accuracy that knows no ''variableness nor 
shadow of turning." 

In a fixed position on land the operation of such a com- 
pass presents no difficulties, but when it comes to mounting 
one on a ship which may move in any direction and at the 



Fig. 2. — A gyroscope mounted 
with three degrees of freedom. 



8 The Boys^ Own Book of Great Inventions 

same time be tossed by the waves, the gyroscope receives 
a ''mixed" motion which deflects it from the meridian. 
But Mr. Sperry has overcome these seemingly insuperable 
difficulties and with the insight of true genius has perfected 
automatic correcting apparatus which neutralizes the effect 
of every variable influence. Like a creature of Hfe this 
gyro-compass seems instinct with initiative and self control. 
Quicker than human thought it adapts itself to every change 
of motion and with unerring accuracy guides the mariner 
both on the surface of the sea and through its depths. 

What the magnetic compass has meant to navigation 
cannot well be overestimated. With the advent of the 
steel ship, however, its use has become constantly more dif- 
ficult. In the days of wooden ships practically the only in- 
fluence that reached the dehcately balanced compass needle 
was that of the earth's magnetic field. But the large masses 
of iron in a modern ship with their attractions for a sus- 
pended magnet have introduced disturbing factors which 
cannot easily be neutrahzed and which have destroyed 
much of the former usefulness of this instrument. The 
magnetic field of the earth is at best exceedingly weak 
and the directive force which it exerts is not sufficient to 
hold the needle steadily on the meridian. Then, too, the 
compass needle, except for a few places on the earth's sur- 
face, does not point to the true north but to the magnetic 
north and tables of declination giving the amount of this 
variation must always be consulted by the mariner in de- 
termining the real course of his ship. 

Therefore, the invention of the gyro-compass which is 
entirely independent of all magnetic influences marks the 
greatest advance in practical navigation in recent years. 
Utilizing the immense directive force of the earth's rotation, 
an instrument of the highest precision has been produced 




The ship stabilizer, the g>To-compass and a simple demonstration of gyroscopic 

action. 



The Gyro Paradox 9 

and one which points to the true north whatever may be 
the ship's position and course or however violently it may 
be tossed by the waves. 

The first experimenter to utilize the principle of the gyro- 
scope in a practical instrument was the great French 
physicist, Leon Foucault, about the middle of the last 
century. He mounted a gyroscope with three degrees of 
freedom and, as already described, was able to give visible 
proof of the earth's rotation. He carried his apparatus to 
England and exhibited it before the Royal Academy where 
he aroused the greatest enthusiasm. In 1878 the well- 
known American author and physical demonstrator, Hop- 
kins, appKed an electric motor to Foucault's gyroscope and 
was able to obtain much more certain results. The gyro- 
compass which he set up operated very well in a stationary 
position but when subjected to the varying motions of a 
wave-tossed ship it became practically useless. 

As previously stated the man who has contributed most 
to the perfection of a gyro-compass of absolute reHability, 
one which automatically adjusts itself to every movement 
of the ship and points with unvarying accuracy to the true 
north is the American inventor, Mr. Elmer A. Sperry. A 
marvelous instrument is this eye of the ship. As one ob- 
serves it in operation in Mr. Sperry' s factory, subjected to 
artificial motions, more severe than any encountered in 
actual service, the unchangeableness with which it holds 
to the meridian gives the appearance of a living, throbbing 
organism endowed with intelligence and self control. But 
here again, just as in every other useful device, this me- 
chanism is the product of himian thought. Back of it 
stands the idea of the inventor translated into material 
expression. It is additional proof of the psychological 
truth that personality is the keynote of the imiverse. 



lo The Boys' Own Book of Great Inventions 

Without the gyro-compass the navigation of the sub- 
marine would have been exceedingly difficult and its sphere 
of action greatly restricted. A magnetic compass is of Httle 
use on underseas craft owing to their steel structure and 
the weak magnetic field of the earth. The equipment for a 
battleship or submarine consists of a master compass and 
a number of repeaters conveniently placed about the ship 
and all under electrical operation and control. The heavy 
wheel of the master compass revolves in a vacuum case 
with a speed of approximately 8600 revolutions per minute. 
Its construction including the automatic correcting devices 
for changing motions is somewhat intricate but its operation 
is strictly in accord with the gyroscopic action already 
explained. 

The Monorail Car. — To the imagination and genius of 
Mr. Louis Brennan, a young man of Irish birth, whose 
youth was passed in Australia, a country of great distances 
and at that time inadequate railway faciUties, we owe the 
spectacle of a car that travels on a single rail, imsupported 
on either side yet balancing itself perfectly, sensitive to the 
slightest strain but secure and stable as a mountain side. 
A paradox it, indeed, seems to be, yet, as we shall see, 
strictly in accord with the laws of gyroscopic action. The 
same force that holds the earth's axis pointing invariably 
to the pole star or balances a swiftly rolling hoop operates 
here to give a wonderful exhibition of inherent strength 
and stability. To conceive of such a project, so revolution- 
ary to all current ideas of locomotion and apparently in 
direct opposition to natural laws, and then to work it out 
to ultimate success is the mark of true genius. 

As Mr. Brennan grew to young manhood surrounded 
by the vast spaces of AustraHa, he pictured in imagination 
the future of this great continent thickly peopled, dotted 



The Gyro Paradox ii 

with large cities and highly organized industrially and agri- 
culturally. But there seemed to be one insuperable obstacle 
to this rapid development, namely, the great cost of railroad 
construction and certain very serious defects in the two- 
rail system. It is a very difficult matter to lay two rails 
exactly parallel and keep them so or to build a road bed 
so solid and secure that the rails will at all points be at 
the proper height. Any considerable deviation from the 
parallel condition results in severe side thrusts or even 
derailment and the depressions in the rails cause jolts and 
rocking, so violent as to make very high speeds dangerous 
and impossible. These defects were more common to the 
railways of Australia, imdoubtedly, than they are to those 
of this country. As Brennan suffered the discomforts 
incident to travel there, he became convinced that the 
future of that vast area depended upon improved trans- 
portation facilities and he determined to solve this 
problem. Thus does the vision of the seer blaze the way 
of progress. 

To overcome these defects there seemed but one way and 
that by means of a one rail system. Therefore, Brennan 
without any hesitation set himself to invent such a system. 
But how to make a car balance itself on a single rail was a 
baffiing problem. Brennan had the idea. The means for 
its material creation were yet to be discovered and per- 
fected. For years the problem was constantly with him. 
He could not get away from it. Having become familiar 
with the action of the gyroscope and its wonderful stabiliz- 
ing power, he bought several models and began to experi- 
ment. At last he was on the right track. And then came a 
long period of experimentation in the laboratory, the work- 
shop in which man hammers into material expression the 
ideas which his genius creates. He made tops and mounted 



12 The Boys^ Own Book of Great Inventions 

gyroscopes in a great variety of ways. He found that a 
picture frame mounted on two sharp pins could be balanced 
perfectly by placing within the frame a spinning gyroscope. 
When he replaced the pins with wheels, tandem fashion, not 
only would the frame balance itself but it would run on a 
stretched wire. So long as the spin was kept up the mechan- 
ism exhibited great stability. If one pushed against it the 
frame pushed back with an equal and opposite thrust. The 
problem seemed nearing solution, but Brennan soon found 
that his car would turn over on its side and leave the track 
at the first curve. Obviously it is impossible to build rail- 
roads mthout curves and therefore a new and very difficult 
problem had presented itself. As will be seen a httle later, 
the cause of this mishap is a direct result of the laws of 
motion governing the gyroscope and its remedy seems very 
simple now. To Brennan it proved an obstacle which he 
was long in overcoming. The very law of motion which 
he was seeking to utilize as the stabilizing force of his car 
seemed likely to defeat his purpose and bring his years of 
thought and work to naught.. But perseverance knows 
no turning back and Brennan had no idea of abandoning 
his purpose. He went to southern France for a short rest 
but the problem of the curve perpetually haimted him. One 
morning he bought a toy gyroscope of a street vender, a 
very crude affair when compared with the elaborate ones 
in his own laboratory, but as he spim it and pondered its 
action in a flash there came to him the way out of his diffi- 
culty. He returned to England and very shortly perfected 
the first model of the Brennan car. 

On May 8, 1907, Brennan exhibited his model before the 
Royal Society and later gave numerous public demonstra- 
tions at his country place. Here was a car that balanced 
itself automatically, pushed back with a very great force 



The Gyro Paradox 13 

against any thrtist tending to drive it from the track, 
rounded sharp curves, climbed steep grades, followed the 
crookedest gas pipe with perfect ease and crossed deep 
ravines on a slender and swaying cable. If a heavy weight 
were placed on one side, the car did not fall but rose sHghtly 
to meet the load. If one thrust down on the edge of the 
car, it pushed back and rose. In roimding a curve the car 
leaned in sKghtly just as a bicycle rider does. Indeed, it 
seemed instinct with intelligence and Hfe. And all on a 
single rail, as stable when at rest as when in motion. 

A closer inspection revealed a two chambered compart- 
ment in the front of the car in which two small fly wheels 
rotated in vacuum cases at the rate of about 7000 revolu- 
tions per minute. These wheels, smaU but heavy, rotate 
in opposite directions and being mounted so as to permit 
of precessional movement constitute the balancing mechan- 
ism of the car. 

Just how they operate will become clear from a consid- 
eration of the following figures and explanation. Brennan 
has simply utilized the very great inertia of a rotating body, 
which is free to precess, in balancing his car. But far from 
being in defiance of gravitation this balancing power is the 
direct result of well known laws of motion. 

Figure 3 shows a gyroscope mounted with three degrees 
of freedom, that is, it may rotate about axis OA and at 
the same time turn on axis BC or DE. If the heavily 
rimmed wheel is set spinning, its inertia will keep its axis 
OA pointing in the same direction and will resist any effort 
to displace it. This resistance, however, will manifest itself 
by causing the gyroscope to turn or precess about one of 
the other axes. Suppose we attempt to force the axis of 
the spiiming gyroscope down by applying pressure at A. 
The result is not a downward but a horizontal movement 



14 



The Boys^ Own Book of Great Inventions 



of the whole mechanism to the left about axis DE. If now 
we apply a vertical upward pressure at A, the precession 
will take place in the opposite direction. Should we en- 
deavor to hasten the precessional movement by exerting 




Fig. 3. 

a sidewise thrust at A, the axis of the spinning wheel will 
either rise or fall. It will rise if we push to the left and 
fall if we push to the right. In any of these cases we are 
subjecting the gyroscope to two rotations at the same time 
and, just as in the case of the bicycle wheel, it attempts to 
rotate on the resultant axis lying between the two. And 
it makes no difference whether the gyroscope be subjected 
to one or several disturbing influences, each will have its 



The Gyro Paradox 



15 



own effect. So long as the spin keeps up the action is au- 
tomatic and instantaneous, the mechanism responding im- 
mediately to every influence, however slight. Its action is 
literally quicker than human thought. The amount of its 
inertia and therefore its stabilizing influence depends simply 




Fig. 4. — Gyroscope to illustrate the balancing action in the 
mono-rail car. 

upon the mass of the gyroscope and the speed with which 
it rotates. 

Now let us consider Fig. 4. This will explain the action 
of the gyroscope in balancing the mono-rail car. By means 
of the vertical axis DE the gyroscope is attached to the 
frame work of the car. The axle OF carries two friction 



i6 The Boys^ Own Book of Great Inventions 

wheels, or rollers Wi and W2 which during the operation 
of the gyroscope will according to various influences come 
in contact with segments Si S2 S3 S4. These segments are 
a part of the framework of the car. The roller Wi is loosely 
mounted on the axle OF so that it is free to turn whenever 
pressed against the adjacent segments of the car frame. 
On the contrary roller W2 is not attached to the axle but 
to an extension of the horizontal portion of the gyroscope 
frame. 

Now let us see what will happen when a car running on 
a single rail and supplied with such a gyroscope is subjected 
to any of the variable influences such as the centrifugal 
force from rounding a curve, wind pressure, or the sudden 
shifting of passengers and freight. Suppose the car sud- 
denly tips to the right from the weight of fifty passengers 
who move to that side of the car. This will bring segment 
5*1 down against roller Wi and because of the friction be- 
tween them the roller will immediately begin to run along 
the segment just as a locomotive wheel runs along the rail. 
But it will be seen that this is the same as a side thrust on 
the axle OF, pushing it to the left and, just as explained in 
Fig. 3, the result will be an upward movement of the axle. 
In other words as the car tends to tip to the right the au- 
tomatic action of the gyroscope gives an upward thrust in 
the opposite direction, which causes the car to tip back to 
the left. This action will bring segment S2 in contact with 
roller W2 giving an upward thrust to the axle OF, but an 
upward thrust, it will be remembered, causes the axle to 
move to the right, thus bringing roller Wi in contact with 
S3 along which it tends to roll. This will increase the 
movement to the right and therefore cause the axle to be 
depressed downward, for a side wise thrust to the right 
brings a downward movement of the gyroscope axle. This 



The Gyro Paradox 17 

downward movement will bring segment S4 in contact with 
roller W2 which will arrest the downward tendency and 
move the axle back to the left and into its original position. 
All this happens instinctively, as it were, and with lightning 
rapidity. Whatever the disturbing influence may be, this 
series of oscillations is set up and continues until the whole 
car is again in perfect balance. 

But how did Brennan solve the problem of the curve? A 
Httle consideration will show that when the car is rounding 
a curve the gyroscope is subjected to an additional influence, 
the result of which is to throw the car over upon its side. 
With the gyroscope wheel spinning as showTi by the arrow, 
the direction of its axis of rotation will be to the left, i. e., 
the direction which a right handed screw will follow in 
being turned. The axis of the curve, however, will always 
be vertical and it does not matter whether its direction is 
up or down our gyroscope in attempting to place its own 
axis along a line lying between the two will derail the car 
and with an irresistible force hurl it over upon its side. 
It will always fall, too, toward the inner side of the curve. 

To solve this problem Brennan mounted in his car two 
gyroscopes of equal masses and linked together so as to 
rotate with exactly the same speeds but, and here is the 
point, he made the wheels rotate in opposite directions. 
Then when the car rounds a curve, as one gyroscope tries to 
tip it off the track in one direction the other is exerting an 
exactly equal force in its effort to derail the car in the op- 
posite direction. Therefore the two forces neutralize each 
other thus destroying the effect of the curve. In all other 
respects one gyroscope has the same effect as the other, 
for the two gyroscopes are mounted on either side of the 
center line of the car and are in perfect balance. Therefore, 
^s the car tips to the right for example causing a downward 



i8 The Boys^ Own Book of Great Inventions 

thrust on one axle, there is a corresponding upward thrust 
on the other axle and since the gyroscopes rotate in oppo- 
site directions the resulting precessional movements will 
always be in the same direction, or better they will always 
be working together. 

Although this type of locomotion at the time of its in- 
vention seemed to possess very decided advantages over 
the two-rail system, the world has not hastened to adopt 
it. Brennan received a grant of $30,000 from the India 
Society with which he built a car one hundred and sixteen 
feet long and balanced by gyroscopes three and one-half 
feet in diameter. This car did all that Brennan had 
claimed. Its stabilizing power was perfect and speeds very 
much greater than any now attainable seemed possible. 
The inherent merits of the gyro-car are still as potent as 
ever and the post-war period may see its extensive intro- 
duction. 

Other Gyroscopic Devices 

The Aeroplane Stabilizer. — In the summer of 19 14 just 
preceding the great war in an international aviation meet 
held in Paris, Lawrence Sperry, son of the inventor, won 
the first prize awarded for the best automatic aeroplane 
stabilizer. The Sperry Automatic Pilot as the device is 
called is another application of the gyroscope. There are 
two gyro units which upon the slightest tipping of the 
aeroplane close electric circuits, thereby starting motors 
which move the regular aeroplane control surfaces just the 
right amount and hold the machine in its proper position. 
These gyros are sensitive to a tip of less than a degree and 
being instantaneous and automatic in their action are im- 
mensely superior to human control. This control covers 
both lateral and longitudinal tipping and in addition by 



The Gyro Paradox 19 

means of another device called the azimuth-gyro the aero- 
plane can be held in any desired direction, whatever may 
be the direction of the wind. In numerous demonstrations 
made in France and in this coimtry this gyroscopic stabilizer 
has shown how completely the uncertain human factor may 
be eliminated from the problem of aeroplane control. In 
the great post war period of aeroplane development this 
stabilizer will undoubtedly have a very important part 
and it is now in use on military aeroplanes of all the allied 
powers. 

The Ship Stabilizer. — Another gyroscopic device of which 
the pubHc is destined to hear and experience much in the 
future is the automatic ship stabilizer. The physical dis- 
comfort incident to ocean travel in rough seas is so great 
as completely to discourage very many people from ven- 
turing upon a very long sea voyage. The time is at hand, 
however, when every transatlantic liner of importance will 
be equipped with a gyroscopic stabilizer which will render 
her decks in the roughest sea as free from pitching and 
rolling as though she were ''a painted ship upon a painted 
ocean. ' ' 

This device consists of a heavy gyro-wheel mounted on 
a vertical shaft set within a casing placed on horizontal 
trunions. The gyro-wheel rotates on a vertical axis, the 
ship in attempting to roll will turn it about a horizontal 
axis lengthwise of the ship, while the casing and with it 
the gyro-wheel within are free to precess about a horizontal 
axis crosswise of the ship. Thus it will be seen that here 
again we have a gyroscope with three degrees of freedom 
and its action with the pitching of the ship is exactly like 
that of the gyros in the mono-rail car. It is the fact that 
the wheel is free to precess that gives it its wonderful 
stabilizing influence. Were the wheel held rigidly in posi- 



20 The Boys^ Own Book of Great Inventions 

tion, though it rotated ever so fast, there would be no op- 
position offered to the action of the waves. This is shown 
on ship board by clamping the gyro rigidly, when the fury 
of the sea again takes full effect. 

The United States government has equipped many of 
its cruisers and battleships with these gyros and their 
ability entirely to prevent rolling and pitching in the storm- 
iest weather has been fully demonstrated. A ship may be 
rolling through an angle of from 30 to 45 degrees on either 
side of the vertical and groaning and creaking in every 
timber when the gyros are turned on and immediately all 
becomes calm. The decks become level, the quivering 
ceases and were it not for the visible evidences of a tur- 
bulent sea we should never suspect its presence. The waves 
seem to lose their impact, no water washes the deck, not 
even spray comes aboard and there is only a gentle rising 
and falling as the major waves pass under the ship. The 
wear and tear to which a ship is usually subjected at such 
a time is all absent. It has been found, too, that the ship 
is propelled through the waves at practically the same speed 
as though she were in still water. And she holds her course 
with very Httle helm. 

The immense significance of this to navigation and ocean 
travel is at once apparent. An invention so calculated to 
rob the sea of its terrors and add to the world's enjoyment 
of it is destined to become a commonplace of the future. 
Many American yachts are now equipped with these 
stabilizers. The very great advantage of having a level 
gun platform on battleships can now be realized and it 
ought to add much to naval efffciency. 

The first successful demonstration of the gyro ship 
stabilizer was made in 1906 by Dr. Schlick in the North 
Sea. The man, however, who has brought this device to 



The Gyro Paradox 21 

its present high degree of perfection is Mr. Sperry who in- 
vented the gyro-compass and the aeroplane stabilizer and 
with whose work we are now familiar. 

The Steerable Torpedo. — The deadly torpedo owes the 
wonderful accuracy with which it is carried to the mark 
to the action of the g}Toscope. As the torpedo is discharged 
a trigger projecting from the side of the firing tube releases 
the spring which starts the gyroscope spinning. Any de- 
viation of the torpedo from the path in which it has been 
aimed tends to change the axis of rotation of the gyroscope, 
and the resulting precessional movement acts upon one 
of two valves connected with the compressed air reservoir 
which drives the torpedo's screw propellers. This admits 
air into a cylinder which forces a piston to move a rudder 
so as to steer the torpedo back into its path. If the torpedo 
swerves in the opposite direction the other valve acts in a 
similar manner. 

The possibiKties of gyroscopic action have by no means 
been exhausted and the future will undoubtedly see many 
new and interesting applications. Never forget, though, 
that the gyroscope presents no mystery and that its be- 
havior is strictly in accord with natural laws. Like every 
other mechanism it is simply a link between the human 
mind and the great thought world of the Creator with 
which we are enveloped. 

Some Experiments with the Gyroscope 

Buy an ordinary toy gyroscope and perform the experi- 
ments described in the folder that accompanies it. Several 
illustrations of what can be done with this toy are shown 
in Fig. 5. Even so simple a toy as this demonstrates the 
great inertia and balancing power of the gyro-top. 



22 



The Boys^ Own Book of Great Inventions 



The Compound Gyroscope. — Buy if possible a compound 
gyroscope similar to that shown in Fig. 2. As already ex- 
plained such a gyroscope has three degrees of freedom. The 




Fig. 5. 

gyro-wheel rotates about one axis and is free to turn about 
two others, either one of which may be rigidly clamped if 
desired. A compound gyroscope may easily be made,, too, 
from one of the toy gyroscopes. Mount such a simple gyro- 
scope in a frame supported by a stand as shown in the figure 
and it will perform with perfect satisfaction all of the ex- 
periments to be described here. 
Experiment i. — Set the gyroscope to spinning with its 



The Gyro Paradox 23 

axis in a horizontal direction. The wheel will tend to re- 
main in this position and will resist any attempt to displace 
it. Now apply a steady downward pressure to one end 
of the axle. The result is not a downward movement, as 
you might expect, but the whole frame moves in a hori- 
zontal plane about the vertical axis and at the same time 
tends to rise. The mechanism seems to be aHve and to 
act in a manner contrary to the laws of material bodies. 

Experiment 2. — Spin the gyroscope again with its axis 
in a horizontal direction and this time push steadily upward 
on one end of the axle. The result is a movement in a 
horizontal plane but in the opposite direction to the pre- 
vious one and there is also a tendency to move downward. 

Experiment j. — Now spin the gyroscope and hang a 
weight on one end of the axle. Not only will the weight 
be supported but the whole frame will move slowly about 
the vertical axis. In other words the gyroscope precesses 
just as the bicycle wheel did. As the spin dies down the 
inner ring gradually drops from the horizontal and the 
precession stops. 

Spin again with the weight on the opposite end of the 
axle and the precession will be in the opposite direction. 

Experiment 4. — Spin the gyroscope with the axis hori- 
zontal and give one end of the axle a sharp sidewise thrust. 
The result will be either an upward or a downward move- 
ment about the horizontal axis depending upon the direc- 
tion of the spin. 

Push the axle in the opposite direction and the movement 
will also be in the opposite direction. 

By performing these simple experiments you will verify 
for yourself the precessional movements of the gyroscope 
that are utilized in the balancing of the mono-rail car. 

Experiment 5. — The effect of the earth's rotation upon 



24 The Boys' Own Book of Great Inventions 

a spinning gyroscope may be beautifully shown with very 
little effort. Secure an ordinary toy gyroscope and attach 
strings to the frame as shown in the cut facing page 8. 
Also provide a small cardboard disc with the cardinal points 
of the compass marked as indicated. Now holding the 
string taut as shown but without the gyroscope spinning 
turn on the heel from left to right. Nothing happens and 
the axis of the gyroscope points indifferently in whatever 
direction it may happen to be. 

Now set the gyroscope to spinning and holding it as 
before give a quick turn on the heel. Immediately one 
end of the axis of the rotating gyroscope comes uppermost 
and remains so. Turn on your heel in the opposite direc- 
tion and with a quickness and energy that will surprise 
you, the uppermost pole will flop over and point downward 
toward your feet. As often as you reverse your direction 
of turning the gyroscope will reverse its axis of rotation and 
virtually rotate in the opposite direction. 

Your turning corresponds to the rotation of the earth 
and has the same effect on the toy gyroscope that the actual 
rotation of the earth has on a gyro-compass. 

To illustrate further, suppose an observer could be located 
out in space and looking directly toward the South Pole 
of the earth. Then if a number of gyro-compasses were set 
spinning any where on the earth's surface their axes would 
swing around until they were all parallel with the earth's 
axis and the compasses all rotating in the same direction 
as the earth's rotation. 



Chapter II 
THE TELEGRAPH 

The epoch-making inventions and discoveries are those 
which have contributed most toward the dissemination of 
ideas, the annihilation of time and space and the advance- 
ment of the economic welfare of the peoples of the earth. 
Judged by these standards no other invention of the last 
century, which might well be called the age of inventions, 
can claim higher rank than the telegraph. But like all great 
inventions it cannot be regarded as the work of a single 
inventor. From the earliest times men have felt the need 
of communicating with each other at a distance. The early 
Greeks, Romans and Aztecs devised means of signaKng by 
means of beacon lights flashed from mountain top to moun- 
tain top and great monarchs sent messages to distant parts 
of their domains by estabhshing relays of courtiers to bear 
them. Many have been the signal systems which men have 
employed in their efforts to reduce the real and effective 
size of the planet upon which they live. 

Not until current electricity and electromagnetism had 
been discovered, however, was any real progress made. 
One discovery or invention leads to another and on these 
as stepping stones the race moves forward. The works of 
Galvanni and Volta led scientists everywhere to experiment 
wath the electric current and one of the earliest results was 
Oersted's discovery in 1819 that a current bearing con- 
ductor possesses a magnetic field and will deflect a compass 
needle. Thus it became possible to signal at a distance 

25 



26 The Boys^ Own Book of Great Inventions 

by making and interrupting an electric circuit so arranged 
as to act upon a magnetic needle. This set men at 
work anew on systems of telegraphy. The most im- 
portant telegraph of this t3^e was the five-needle instru- 
ment of Sir Charles Wheatstone, which he patented in 

1837. 
In this telegraph a loop at the receiving end, which formed 

a part of the telegraph circuit, had suspended within it a 
magnetic needle. By closing the circuit the needle was 
deflected to one side or the other depending upon the direc- 
tion of the current. Five separate circuits and needles 
with a sixth return wire were used in the first line. A code 
was devised and it became possible to send messages over 
considerable distances. Wheatstone continued to improve 
his instnmient and by 1845 he had it reduced to a single 
wire system. The single needle by repeated deflections 
was made to point out any desired letters arranged on a 
dial. This system, although much inferior to the Morse 
telegraph invented and perfected at the same time, con- 
tinued in use in England for many years. 

Following Oersted's discovery of the magnetic properties 
of the electric current Arago, a French physicist, discovered 
that a piece of soft iron could be magnetized temporarily 
by passing about it a voltaic current. It was but another 
step for Sturgeon to invent the electromagnet without 
which so many modern electric devices would be impossible. 
As every school boy knows this consists of a soft iron core 
surrounded by a number of turns of uisulated wire. The 
larger the nimaber of turns of fine wire used, the more sen- 
sitive it becomes, a very weak current serving to actuate 
its armature. Then followed the perfection of the Daniell 
cell, a constant current cell which will maintain a steady 
current for long periods of time. 



The Telegraph 27 

The ground work had now been done and the world was 
ready for the advent of the man of genius, the inventor 
who could take these newly discovered laws and first crude 
instruments and fashion them into the masterpiece which 
would "mark an era in human civilization and contribute 
to the comfort and happiness of milHons.'^ 

The world did not have long to wait. Samuel F. B. 
Morse, born in 1791 at Charlestown, Mass., close to the 
birthplace of Benjamin Franklin, was destined to make 
*'the first great commercial appHcation of electricity." He 
was educated at Yale and there under the tutorship of 
Jeremiah Day, the professor of natural philosophy, re- 
ceived his first knowledge of the electric current. But his 
great interest was in art, and after graduation he devoted 
himself entirely to the study of painting, going to England 
in 181 1 with the great American painter, Washington 
Alls ton, to continue his studies. Upon his return to America 
the following year he met with bitter experiences, finding 
the profession of painting unprofitable and the public in- 
different to the products of his brush. In 1829 he again 
went to Europe for further study in the art galleries of 
Paris and Rome. 

Three years later Morse found himself aboard the packet- 
ship Sully bound for America. One of his fellow passengers 
was Dr. Charles T. Jackson of Boston, who had witnessed 
Ampere perform experiments with electricity while in Paris. 
Dr. Jackson had secured for himseK an electromagnet and 
one day in the cabin of the ship he exhibited it and de- 
scribed its action. And here we have one of the psycho- 
logical moments in history, for Morse was immediately 
seized with the idea of transmitting messages over a wire 
by means of the electric current. Since every human 
achievement is the product of an idea, we may consider 



28 The Boys^ Own Book of Great Inventions 

the real invention of the telegraph as having been nnade 
at that moment. Its material creation was bound to 
follow. True, others had conceived of the same idea before 
but they did not carry it through to success. Before leaving 
the ship Morse had made drawings of a crude telegraph 
instrument and had plans for a recording as well as a signal- 
ing system. 

Like most great inventors, Morse was afSicted with pov- 
erty and could devote but little time to experimentation. 
In 1835 he was appointed professor of the arts of design in 
the infant University of the City of New York. Here he 
set up his crude instruments and was able to send messages. 
The acquaintance which he made with Professor Gale, the 
instructor in chemistry, was a very great help. Morse's 
scientific training had been very meager and Gale brought 
him valuable assistance in this respect. Through Gale, 
Morse became acquainted with the work and discoveries 
in electricity of Prof. Joseph Henry, who had brought the 
electromagnet to great perfection, and had invented a 
system of signaling by means of it. 

Morse had been working with an electromagnet which 
had but a few turns of coarse wire and was therefore very 
weak in its action. But several years before Professor 
Henry had demonstrated that a large number of turns of 
fine wire increased many times the sensitiveness of the 
instrument. Morse adopted this improvement and pro- 
duced an electromagnet known as a relay which was suffi- 
ciently sensitive to respond to the weak line current. This 
fine current when conducted over considerable distances 
was too feeble to operate the heavy sounder, but it would 
actuate the weak spring armature of the relay, and this 
armature was made to make and break a local circuit in 
which was placed a sounder and a strong battery. It was 



The Telegraph 29 

this invention of the relay which made long distance teleg- 
raphy possible. 

One day early in the autumn of 1837 there wandered into 
Morse's laboratory a young man by the name of Alfred 
Vail and as he observed a demonstration with the telegraph 
he became much interested in the new invention. He asked 
to be made a partner in the enterprise for he saw great 
commercial possibiKties in it. Morse very readily assented 
to the proposal. Young Vail went to his father, an iron 
master of Morristown, N. J., for financial assistance and 
received it. Two thousand dollars were provided and Vail 
went to work in his father's foundry with all the enthusiasm 
of youth. He possessed considerable abiHty as a mechanic 
and made several improvements in Morse's crude model. 
The Morse code of dots and dashes as we have it today was 
worked out very largely by Vail. Assisted only by an ap- 
prentice boy, William Baxter, and an occasional visit from 
Morse, by January of 1838 Vail had a working telegraph. 
The two partners gave a demonstration that entirely satis- 
fied the elder Vail and the telegraph was well on the way 
to success. 

The essential for commercial success, however, was popu- 
lar interest and to the development of this Morse next 
turned his attention. The pubHc is always skeptical of 
new inventions and to overcome its apathy and indiffer- 
ence is a task as difficult frequently as the invention itself. 
New York and Philadelphia showed no interest in the 
^'scientific toy." Morse then went to Washington with 
his telegraph and sought to enHst the support of the Com- 
mittee on Commerce of the House of Representatives. He 
thought Congress should be willing to finance the building 
of an experimental line. At length Morse succeeded in 
securing the active interest of the chairman of the com- 



30 The Boys^ Own Book of Great Inventions 

mittee, Hon. Francis 0. J. Smith. The rest of the com- 
mittee was soon convinced of the utility of the new inven- 
tion and a bill was introduced appropriating $30,000 for 
the construction of a line between Baltimore and Washing- 
ton. Morse now seemed on the flood-tide of success and 
a company was formed for the promotion of the enterprise. 

Stormy days, though, were ahead for Morse and his 
associates. Instead of remaining in America to drive his 
project through to an early and final success, Morse sailed 
for Europe to secure foreign patents and protect his rights 
abroad. In these efforts he was entirely unsuccessful and 
returned to America, only to find Dr. Jackson a claimant 
to a share in his invention and Congress indifferent to the 
appropriation for the experimental Une. In the midst of 
poverty and disappointment, Morse was compelled to seek 
art pupils as a sole means of averting starvation which he 
only narrowly succeeded in doing. 

But Morse would not give up. He realized as no one 
else the tremendous possibilities of his invention. By 
means of letters and personal interviews with members of 
Congress he exerted every possible influence toward the 
passage of his biU. But many of the congressmen regarded 
the telegraph as the visionary project of a crank and were 
afraid, to go on record as favoring it. At length in May of 
1843, when Morse had been reduced to extreme poverty 
and had exhausted every resource of influence and per- 
suasion, Congress passed his bill and the $30,000 for the 
first real telegraph fine was appropriated. 

Still disaster seemed likely to follow, for unexpected ob- 
stacles in the construction of the line presented themselves 
and much of the $30,000 was wasted without practical 
results. At length the promoters of whom Ezra Cornell, 
founder of Cornell University, was one, decided to string 




telegraph device at the 



-"• L^L^'r ^-t:-.t5;r*,-— 



The Telegraph 31 

the wires on poles instead of running them underground as 
originally planned. Finally on May 23, 1844, just one year 
lacking a day from the time Congress voted the appropria- 
tion, the first telegraph line in America was completed. 
On the following day, the anniversary of the appropria- 
tion, Morse sitting at the transmitter in the Supreme Court 
room in the Capitol telegraphed to Vail in Baltimore this 
immortal message, "What hath God wrought?" The tele- 
graph was an accompHshed fact and a new era in the 
affairs of men had been ushered in. 

The operation of the telegraph is too well known to most 
boys to require much explanation here. And yet familiar 
as we are with it the telegraph always has a wonderful 
fascination. Even yet there is something awe-inspiring and 
mysterious about this sending of one's ideas over a wire. 
But since electricity travels with the velocity of Hght and 
can be made to flow or not at the will of an operator, sig- 
naling at a distance becomes just as feasible as sending the 
human voice through limited distances of space. One is 
really no more mysterious than the other. One is simply 
more common than the other. That is all. 

In Fig. 6 are represented two stations which may be any 
distance apart. At each station there are key, relay and 
sounder. When there is no message being sent both 
switches are closed, and a continuous current flows in the 
line and also through the local circuits in which the sounders 
are placed. The negative side of the batteries at one station 
is grounded and the positive side at the other, the earth 
being used as a part of the circuit. If the operator at A 
wishes to send a message he opens his switch as shown in 
the diagram thus breaking the current at that point and 
demagnetizing every electromagnet on the Kne. Then as 
he presses his key current flows through the line and the 



32 



The Boys' Own Book of Great Inventions 



relays. This energizes the relays, drawing down their weak 
spring armatures and closing the strong local circuits which 
contain the heavy sounders. As the armature of the 
sounder is drawn down a sharp cKck results. By making 




Fig. 6. — Diagram of telegraph line and stations. 

these short or long the dots and dashes used in producing 
the signals of the code are made. Both relays and both 
armatures operate at the same time and if there are in- 
termediate stations the instnmaents in those stations will 
also operate. Any operator on the line may read any mes- 
sage that is passing whether it is intended for him or not. 
But only one switch may be open at a time, for if the Hne 
were broken at more than one point it would be impossible 
to make and break the circuit. As already stated, the relay 
is an electromagnet wound with a large mmiber of turns 



The Telegraph 33 

of fine wire making it sensitive to the very weak line cur- 
rent. Then as shown in the diagram the armature of the 
relay makes and breaks the local circuit. This is a short 
circuit right within the station and the batteries for it are 
usually underneath the operator's desk. The Une current 
is now-a-days supplied by a dynamo instead of by batteries. 
When an operator is through sending a message, he closes 
his switch so the hne can be broken at some other point and 
another operator may use it. 

In Morse's original instrument the armature of the 
sounder carried a pen which made marks on a moving 
strip of paper, a short one for a dot and a long one for a 
dash. Morse regarded this as one of the excellent features 
of his system but operators very soon found that they could 
take messages by ear with great facility and the recording 
attachment was abandoned. 

Duplex Telegraphy. — As invented by Morse it was im- 
possible to send more than a single message over a line at 
one time, but in 1855 J. B. Stearns of Massachusetts per- 
fected a system by which two messages could be sent at 
the same time. 

A consideration of Fig. 7 will make clear the theory of 
duplex telegraphy. The current from the battery at A 
divides and passes around the electromagnet in opposite 
directions, the two branches being balanced so that each 
receives the same quantity of current. The upper and 
lower halves of the magnet being wound in opposite direc- 
tions tends to create a north pole and a south pole of equal 
and opposite strengths at each end and therefore the result 
is to keep the magnet in a neutral condition and to prevent 
its armature from being attracted. The conditions at the 
opposite station are exactly similar. It will be observed 
that when the key at station A is pressed there are two 



34 



The Boys' Own Book of Great Inventions 



paths for the current to follow. One is about the upper 
half of the magnet at A over the line about both branches 
of the magnet at B down to the earth and back to the 
negative side of the battery at A. The other is about the 



i 






i$>^ 



:=- A 



1 



= 



bzh: 



Fig. 7. — A duplex telegraph system. 

lower half of the magnet at A down to the earth and back 
to the battery. Thus the fact that the operator's switch 
at station B is open does not interfere with the work of 
the operator at station A. Now suppose the operator at 
A is sending a message. His own electromagnet and arma- 
ture remain inactive. But if at the same time the operator 
at B begins to send, the current from his battery passing 
about the upper half of his magnet over the line and about 
both branches of the magnet at A will actuate that magnet 
and put its armature in operation. The current from bat- 
tery B is now flowing about the two branches of magnet A 
in the same direction and therefore magnetizes it. 



The Telegraph 35 

There are other devices for accomplishing the same pur- 
pose and a little later Edison invented a quadruplex system 
by which four messages could be sent over the same wire 
at the same time. The saving in copper wire, cost of 
operation and rapidity of transmission resulting from these 
systems was very great and they were quickly adopted 
both at home and abroad. Had Edison done nothing else 
he would be entitled to lasting fame. 

The Atlantic Cable. — No account of the telegraph would 
be complete which did not tell something of the clearness 
of vision and indomitable perseverance of that Httle group 
of men, who, against every obstacle of fate and man, ac- 
compHshed the Herculean task of laying the first Atlantic 
Cable. 

The first submarine cable was laid by Morse in New 
York Harbor in 1842 during those dark days of Congres- 
sional indifference to his great invention. In 1850 a suc- 
cessful cable was laid across the EngHsh Channel and two 
years later England and Ireland were connected by cable. 
In this same year a project was started to establish tele- 
graphic communication between St. John's, Newfoundland, 
and New York, a part of the Hne to consist of a submarine 
cable across the GuK of St. Lawrence. Running out of 
funds, F. N. Gisborne, the promoter, applied to Cyrus W. 
Field, a retired merchant of New York, for financial aid. 
The idea at once seized Field that an Atlantic Cable binding 
together the two continents was feasible and practicable. 
Both the British and American governments responded to 
his appeal for assistance and vessels from each navy were 
detailed to make soundings of the ocean bottom between 
Newfoundland and Ireland. The report was exceedingly 
favorable and Field with Morse as electrician formed a 
company for the prosecution of the enterprise. 



36 The Boys^ Own Book of Great Inventions 

Field went to England to secure capital and there or- 
ganized the Atlantic Telegraph Cable Company which 
took the place of the American Company. He also enlisted 
the support of Charles T. Bright, a young EngKshman as 
engineer for the company. But more important than the 
services of Bright was the association of Professor WiUiam 
Thomson, later Lord Kelvin, as an enthusiastic member of 
the enterprise. Professor Thomson was one of the foremost 
scientists of the time and without his able assistance the 
work could not have been carried to completion. 

In August of 1857 the first attempt at la3dng the cable 
was made. For the gigantic task England loaned the 
Agamemnon, one of her largest warships, and the United 
States the Niagara. The Niagara did the actual work of 
cable-laying and stowed away in her hold were 2500 miles 
of cable consisting of seven copper wires insulated with the 
newly discovered gutta-percha and covered with tarred 
hemp. The little fleet steamed away from the Irish coast 
amid much ceremony and all went well until nearly four 
hundred miles of cable had been paid out. Then as the 
stern of the Niagara was lifted on a high wave the cable 
parted and could not be recovered. There was nothing 
to do but to return to port and abandon the enterprise 
for that year. 

A second attempt was made in June of the next year and 
this time the two ships met in mid ocean, spliced the cable 
and proceeded in opposite directions. A terrific gale nearly 
wrecked the Agamemnon before reaching the meeting place, 
but on June 26th the splice was made and the ships started. 
Twice at distances of three and fifty miles respectively the 
cable parted and the ships steaming back to the meeting 
place respHced the cable and started anew. But when at 
a distance of four hundred miles the cable again parted, 



The Telegraph 37 

Field and his associates were compelled to abandon the 
enterprise and return to England. 

Several million dollars had been lost and much valuable 
time. It was by no means easy to raise funds for a new 
start, but Field and Thomson undismayed once more 
kindled faith in the members of the company and in July 
of the same year the Agamemnon and Niagara met in mid 
ocean for a third start. Although much anxiety prevailed 
on ship board no mishap attended either ship and on 
August 6th the Agamemnon reached the Irish coast and 
the Niagara the Newfoundland coast in safety. 

Telegraphic communication was at once set up and an 
interchange of greetings passed between Queen Victoria and 
President Buchanan. Every honor both at home and abroad 
was accorded the promoters of the enterprise. But in the 
midst of these celebrations when the cable was scarcely a 
month old the last message passed over it. Ignorance of 
the electrical requirements for cable transmission had re-, 
suited in the use of too high voltages and the insulation 
of the cable had been ruined. The keenest disappointment 
prevailed everywhere and all but Field and his companions 
despaired of ultimate success. 

With the Civil War on and previous disasters fresh in 
the public mind it was not easy for Field to enlist interest 
in a fourth attempt. This he did, however, and in July of 
1865 the Great Eastern, a mammoth ship too large for 
existing piers and harbors, was commissioned for the under- 
taking and the expedition once more proceeded from the 
Irish coast. After nearly two-thirds of the cable had been 
laid the Great Eastern's machinery broke down and as she 
was tossed by the waves the cable parted and was lost. 

A man of less indomitable faith and courage than Field 
would have given up, but he began all over. A year later 



38 



The Boys' Own Book of Great Inventions 



on July 13, 1866, the Great Eastern started on her second 
venture and this time it was crowned with success. In 
just two weeks the cable was landed in Newfoundland and 
from that day to this the world has never been without 




Fig. 8. — ^Western Union Telegraph Office at 195 Broadway as it appeared 

in 1880. 

transatlantic cable service. The lost cable of the previous 
year was recovered and since many more have been laid. 
What the world owes to these pioneers of science and 
invention it will never know. It is difficult to estimate the 
tremendous influence of the telegraph in the development 
of the modern business world. The operation of the great 



The Telegraph 39 

trans-continental railway systems would have been im- 
possible without it. The opening of the vast areas of the 
West and their assimilation as an integral part of the nation 
would have remained dreams of the pioneer days. National 
unity as we understand it today would never have been 
realized. In a world without the telegraph the big city 
dailies, such powerful factors in the molding of public 
opinion, would have no existence. Commercial enterprise 
would have remained a dwarf. ProvinciaHsm and not in- 
ternationaHsm would be the key-note of the future and that 
freest intercourse of nations which is to be the basis of ulti- 
mate world peace forever impossible. The world is prone 
to forget the debt it owes to the heroes of science who have 
made possible the great conquests of peace and war. What 
were but yesterday the marvels of inventive genius are 
become the commonplaces of today. 



Chapter III 
THE TELEPHONE ROMANCE 

If to flash one's ideas over a wire by means of dots and 
dashes produced through the operation of an electromagnet 
seems mysterious, then the transmission of the human voice 
along a similar wire by means of millions of tiny electric 
waves and its exact reproduction, hundreds and even 
thousands of miles away is little short of miraculous. To 
make an iron disc vibrate in response to the very slight 
energy of the human breath, three thousand miles distant, 
and actually to talk with the same tone and accent as 
though the speaker himself were present sounds Hke a tale 
from fairy land. But this is no longer a dream. It is rather 
a dream come true. We are living now and have been for 
nearly a century in a realm of scientific discovery and in- 
vention more wonderful than any fairy land constructed 
in the imagination of the most fanciful dreamer. And yet 
this is the age of dreamers, dreamers whose souls have 
caught the vision of mighty achievements and whose deeds 
are marshalling the gteat and unseen forces of the universe 
into the army of human service. 

No seer of any age ever dared to dream of a project more 
fanciful or seemingly impossible than Alexander Graham 
Bell when he began to speculate on the possibilities of 
transmitting the human voice by means of electricity. 
And yet Bell was not an electrician. As he, himself, said, 
''Had I known more about electricity and less about sound, 
I never would have invented the telephone." Bell was a 

40' 



The Telephone Romance 41 

master of acoustics, an elocutionist of some note and a 
teacher of deaf-mutes by 'a system of ''Visible Speech'' 
invented by his father. His whole family for several gen- 
erations had been interested in human speech. 

Bell was born in Edinburgh, Scotland, in 1847. After at- 
tending the pubHc schools of his native city and subse- 
quently studying on the continent, he went to London where 
he made the acquaintance of Sir Charles Wheats tone, the 
inventor of the English telegraph. Here he learned that 
Helmholtz had vibrated tuning forks by means of electro- 
magnets and was thereby able to produce sound. Because 
of his very great interest in human speech and everything 
having to do with it, this production of sound by an electric 
current deeply impressed Bell and there was born in his 
imagination the idea of a musical telegraph. He thought 
it possible to devise a mechanism which would transmit 
several messages over a wire at the same time and by utiliz- 
ing the phenomena of sympathetic vibrations enable each 
message to be received independently of the others. He 
knew that if he sang any particular note close to the strings 
of a piano, the corresponding string would answer him. 
Of little significance to anyone but a genius, this fact 
meant to Bell that there might be invented a musical 
telegraph which would carry simultaneously over one wire 
as many messages as there are notes on a piano. A wild 
dream no doubt and yet it was the nucleus about which 
the development of the telephone grew. 

At the age of twenty- two Bell lost two brothers from tu- 
berculosis and was threatened himself with the dread 
plague. Leaving his native land he came to Canada with 
his father in the quest for health. In the Kttle Canadian 
town of Brantford he lived for a year, fighting down his 
tendency to consumption and busying himself by teaching 



42 The Boys^ Own Book of Great Inventions 

his sign language to a tribe of Mohawk Indians. In 187 1 
through an acquaintance made by his father, while lecturing 
on ''Visible Speech" in Boston, the Board of Education of 
that city offered Graham five himdred dollars to introduce 
his system of teaching deaf mutes in a school which had 
just been estabHshed there. Bell accepted and from that 
time on he has been a resident of the United States and 
a loyal American. 

Bell's work met with the utmost success and very shortly 
he was appointed to a professorship in Boston University 
where he might train others to teach his system. A little 
later he estabHshed a school of his own. For two years 
he had Httle time to think of the invention of a musical 
telegraph and the great success which attended his pro- 
fessional work seemed likely to result in abandonment of 
the idea. 

About this time, however, there came to Bell as a private 
pupil a little deaf-mute, Georgie Sanders, who lived with 
his grandmother in Salem. Bell was engaged to give him 
private lessons and as a part of his remuneration was to 
Hve in the Sanders home. Here Bell was allowed the 
basement as a workshop and he also made a fast friend of 
the boy's father, Thomas 'Sanders, without whose sympathy 
and financial aid the invention of the telephone would have 
been impossible. Another private pupil of this time was 
Mabel Hubbard, a girl of fifteen who had lost her hearing 
and speech in infancy. She showed the keenest interest 
in Bell and all his work and four years later became his 
wife. Her father, Gardiner G. Hubbard, was a prominent 
lawyer of Boston and with Sanders gave the heartiest en- 
couragement to Bell in the prosecution of his work on the 
musical telegraph. 

Very soon the Sanders' basement became the scene of 



The Telephone Romance 43 

all Bell's spare time. Here he brought his electrical ap- 
paratus and devices for the transmission of sound. No one 
was admitted to this sanctum, save the members of the 
Sanders' family, and he guarded with the greatest caution 
his ideas and work. In his enthusiasm for the great idea 
that possessed him, he neglected his teaching until only 
his two private pupils remained. Sanders and Hubbard 
financed his work. Giving Httle time to sleep and forgetful 
of the other members of the ho\isehold, Bell worked in- 
cessantly toward the perfection of his idea. 

Both transmitter and receiver of Bell's musical telegraph 
consisted of an electromagnet, to one pole of which was 
fastened a piece of steel clock spring. One end of the spring 
extended over the opposite pole of the magnet and was 
free to vibrate. A make and break key was provided for 
the transmitter which when closed energized the magnet 
and caused the spriag to vibrate after the fashion of a 
modern electric bell. This vibration produced a note, the 
pitch of which corresponded to the pitch of the spring. 
By varying the length of the spriag an indefinite number 
of notes could be produced. This vibrating spring at the 
same time made and broke the maia line circuit. It was 
Bell's theory that if one of these electromagnets, or ^'vi- 
brating reeds," as he called them, were connected in series 
with one of exactly the same pitch used as receiver at some 
distant point on a telegraph line and the reed set to vibrat- 
ing, then the receiving instnmient would be set in to vi- 
bration and produce an audible note corresponding to that 
of the transmitter. And Bell reasoned further that if six 
or eight transmitters, each having a different pitch, were 
connected to a telegraph line and an equal number of re- 
ceiving instruments tuned to correspond were placed at 
various points, each receiver would pick out from the medley 



44 The Boys^ Own Book of Great Inventions 

of passing vibrations its own particular note and be thrown 
into sympathetic vibration. A perfectly plausible idea. 
Duplex telegraphy would be entirely overshadowed and 
the successful inventor would at once rise to wealth and 
fame. 

But the longer Bell worked at his musical telegraph the 
more he became convinced that he was on the wrong track. 
Gradually there came into his mind the idea of sending the 
spoken word itself over the electric wire and reproducing 
it at the opposite end. His interest in the musical telegraph 
vanished and he devoted himself with even greater eagerness 
to the perfection of an actual talking telegraph. Bell 
reasoned thus, *'If I can make a deaf-mute talk, I can make 
iron talk." Sanders and Hubbard, however, had no faith 
in his new idea and refused their further support unless he 
should continue his work on the musical telegraph which 
seemed to promise great practical results and to possess 
tremendous commercial possibilities. Therefore Bell worked 
faithfully for a certain period each day on the original idea 
and then turned with intense eagerness to his experiments 
in the transmission of human speech. 

During all this time, too, Bell had been trying to perfect 
better methods in his system of ''Visible Speech.'^ He had 
experimented with a speaking trumpet as transmitter and 
a harp as receiver. These experiments led him to the dis- 
covery that a meinbrane thrown into vibration by the 
voice would make the sound waves plainly visible. He 
thought the deaf might be taught an alphabet of visible 
vibration. Dr. Clarence J. Blake of Boston suggested the 
use of a real ear as vibrating membrane and provided one 
for Bell's use. With one end of a straw fastened to the ear 
driun and the other free to move over a smoked glass, 
Bell was able to produce markings on the glass when he 



The Telephone Romance 45 

spoke into the ear. Nothing of importance resulted for 
visible speech but this idea of a vibrating membrane was 
like the inspiration of genius to Bell at this point in his 
invention of the telephone. If a deUcate ear drum would 
set into vibration the heavy bones behind it, why would 
not a vibrating iron disc set an iron rod or electrified wire 
into vibration? Although the means were all yet to be 
devised he was at last moving in the right direction. 

About this time while on a trip to Washington Bell met 
Prof. Joseph Henry, who for a generation had been Amer- 
ica's leader in electrical research, and received from him 
the utmost encouragement. To Bell's statement that he 
did not possess the necessary electrical knowledge for the 
perfection of his invention Henry repHed, *' Get it." Noth- 
ing could have heartened Bell more and he returned to his 
laboratory with a renewed spirit of perseverance that never 
forsook him. 

This was in 1874 and Bell had moved his laboratory to 
Boston where he rented a room in the attic of William's 
electrical shop and employed Thomas A. Watson, an ap- 
prentice of the estabhshment, as assistant. Sanders and 
Hubbard were still supplying funds and Bell continued his 
work on the musical telegraph. 

One hot afternoon in June, 1875, J^^^^ 2, to be more ex- 
act, Bell and Watson were at work as they had been for 
months in a vain effort to tune into sympathy with each 
other the vibrating clock springs on the receivers and 
transmitters of their telegraph system. Watson was send- 
ing and Bell receiving. As Watson pressed the sending 
key, the contact points fused together and when he released 
it the current continued to flow. Consequently the spring 
would not vibrate but was held down by the electromagnet. 
In his efforts to locate the trouble Watson plucked the 



46 The Boys^ Own Book of Great Inventions 

spring causing it to vibrate. Bell came rushing into the 
room. A faint sound had actually passed over the wire 
and his keen ear had caught it. ''What did you do then?" 
he demanded of Watson. ''Don't change anything. Let 
me see." 

In that moment the telephone was born. The plucking 
of the iron spring had varied the intensity of the current, 
which by accident was passing continuously through the 
electromagnets and line, and this varying current had 
caused the spring of the receiving magnet to be attracted 
with a constantly changing force and therefore to be thrown 
into vibration in exact unison with the sending spring. 
Just as the air is made to vibrate by the human voice so 
this vibrating reed produced sound waves. The funda- 
mental principle of the modern telephone was operating 
in that crude apparatus and the whole world may be grate- 
ful that the right man was listening to its first faint cry. 
All that remained was to perfect discs or springs sensitive 
enough to be vibrated by the human voice and articulate 
telephony would be an accomplished fact. 

The rest seems easy now but for forty long weeks the 
inventors worked, experimenting with every variety of 
vibrating disc and still the mechanism would not talk. 
And then on March lo, 1876, Watson, located in the attic, 
heard distinctly through the telephone receiver this message 
from Bell who was in the basement, "Mr. Watson, come 
here, I want you." Watson dropped his receiver and 
rushed to the basement, three flights below, shouting, "I 
can hear you. I can hear the words." 

In the work of bringing the invention to perfection which 
immediately followed, Watson says, "I made and tested 
telephones with all sizes of diaphragms made of all kinds 
of materials — diaphragms of boiler iron several feet in 



The Telephone Romance 47 

diameter, down to a minature affair made of the bones 
and drum of the human ear, and found that the best results 
came from, an iron diaphragm of about the same size and 
thickness as is used today. We tested electromagnets and 
permanent magnets, of a multitude of sizes and shapes, 
with long cores and short cores, fat cores and thin cores, 
solid cores and cores of wires, with coils of many sizes, 
shapes and resistances and mouthpieces of an infinite 
variety. Out of the hundreds of experiments there emerged 
practically the same telephone you take off the hook and 
listen with today, although it was the transmitter as well 
as the receiver." 

On March 7, 1876, Bell had received a patent on his in- 
vention which has been called ^'the most valuable single 
patent ever issued." Although totally unlike the telegraph, 
Bell described his invention as ^'an improvement upon the / 
telegraph." 

Just at this time the Centennial Exposition was opening 
in Philadelphia and this offered to Bell precisely the oppor- 
tunity he needed to place his invention before the public. 
Hubbard, who was one of the commissioners of the ex- 
position, was able to secure an out of the way corner in the 
Education Building for the exhibition of the telephone. 
Being without funds Bell had not planned to visit the ex- 
position himself, but as the train bearing Miss Hubbard 
was leaving the Boston Station, overcome by her grief on 
learning that he was not to accompany her, in rather 
dramatic fashion he boarded the train. 

Arrived in Philadelphia Bell set up his apparatus and 
awaited the judges' tour of inspection. The pubHc, always 
indifferent to new inventions, took no more interest in 
Bell's telephone than they had done in Morse's telegraph 
a generation before. The judges, too, were skeptical and 



48 The Boys^ Own Book of Great Inventions 

regarded the apparatus as a toy of no particular significance. 
*'What if speech could be sent over a wire?" "Of what 
value could that be?" But just as the judges were about 
to leave Bell's exhibit without examining it, one of those 
dramatic moments of history arrived. Dom Pedro, the 
young Emperor of Brazil, with a company of gaily attired 
attendants arrived on the scene and greeted Bell with great 
fervor. The Emperor had visited Bell's school for deaf- 
mutes in Boston years before and had been much interested 
in the system of "Visible Speech." Dom Pedro was willing 
to test the apparatus and placing the receiver to his ear 
Hstened as Bell spoke. He dropped the receiver and in 
complete amazement exclaimed, "My God, it talks." 

The judges were now all interest. Skepticism vanished. 
Each in turn listened to the human voice as it came pul- 
sating over the wire carried by a million electric waves. 
Among the judges were Joseph Henry and Sir William 
Thompson, the latter declaring the telephone to be "the 
most wonderful thing he had seen in America." The great 
invention then became the most talked of exhibit at the 
exposition and was given a prominence for the remaining 
time worthy of its merit. Scientists, statesmen, business 
men — everyone flocked to see and hear this latest wonder 
of modern invention. Bell's name was on every Kp and 
over night he had risen to world fame. 

Although Bell had created the sensation of the exposition, 
the pubHc in general were still skeptical. No one could 
see any possible use for the invention anyway. Therefore 
if Bell's telephone were to make fortune as well as fame for 
its promoters something must be done to popularize it. 
Hubbard undertook a campaign of publicity which had 
for its object the annihilation of the skeptics and the win- 
ning of pubHc favor. One move was to arrange a series 



The Telephone Romance 49 

of ten lectures to be given by Bell and Watson. A body of 
scientists, the Essex Institute of Salem, gave the first in- 
vitation for a demonstration. Bell gave the lecture and 
Watson acted as the man behind the scenes, being located 
in the Boston laboratory. A telegraph line connecting the 
lecture hall and the laboratory had been borrowed for the 
occasion. Watson would Hsten at the telephone and at the 
request of Bell played various musical instruments and, 
although not a singer, was required to render such favorite 
songs as "Auld Lang Syne" and "Yankee Doodle." These 
were heard by the audience in Salem and at the close of 
the lecture the members were invited to test the telephone 
for themselves. 

This lecture aroused the greatest interest and invitations 
to repeat it came like a flood. Editors of newspapers awoke 
and gave it pubKcity. Indifference ceased and Bell became 
the most popular lecturer of the season. And yet this 
interest had no other object than entertainment. People 
flocked to hear Bell as they would to a circus. No one could 
see that the telephone possessed any commercial possibil- 
ities. But these lectures did bring results. They brought 
publicity and with their financial returns Bell was able to 
marry and sail for Europe on a wedding trip. 

The first real telephone fine to be established was be- 
tween the WilKams electrical shop in Boston and Mr. 
WilHams' home in Somerville. Then in the month of May, 
1877, the publicity campaign began to bear fruit. A man 
named Emery from Charlestown came into Hubbard's office 
one afternoon and laid down twenty dollars for the lease 
of two telephones. This was the first money ever received 
for a commercial telephone and in the encouragement which 
it gave to the promoters its value was more than a milHon 
dollars would have been a dozen years later. In this same 



50 The Boys^ Own Book of Great Inventions 

month, too, six phones were loaned to the owner of a 
burglar alarm system operating between six Boston banks 
and a central station. Here the first crude exchange was 
established. In a short time exchanges were established 
in New York, New Haven, Bridgeport and Philadelphia. 
One man secured the telephone rights for the entire state 
of Michigan for the asking and sold them a few years later 
for a quarter of a miUion. By August of that year 778 
telephones were in actual use and Hubbard organized the 
^'Bell Telephone Association'' with Bell, Hubbard, Sanders 
and Watson as partners. Sanders was the only member of 
the company who had money but their capital was not 
sufficient to develop the enterprise and no one would buy- 
stock. They offered the patent to the powerful Western 
Union Telegraph Company for $100,000 but the "electrical 
toy" was rejected. 

The Western Union enjoyed a monopoly of wire com- 
munication and supplied many business firms with printing 
and dial telegraphs of several forms. These were so "su- 
perior" to the telephone that it was thought they could 
never be displaced. Then the unexpected happened. 
Several patrons of the Western Union removed the tele- 
graph machines and replaced them with telephones. At 
once the Western Union awoke. If a real competitor had 
entered the field they must control it. Immediately the 
"American Speaking-Telephone Company" was organized 
with $300,000 capital and with Edison, Gray and Dolbear 
as electrical advisers. Edison was just beginning his great 
career. Gray had invented a musical telegraph and Dolbear 
had done work on a telephone which did not prove suc- 
cessful. 

The result was magical. When the Western Union en- 
tered the telephone field skepticism vanished. Men were 




Fig. 9, — Bell lecturing and demonstrating with the telephone before the 
Essex Institute of Salem. 



The Telephone Romance 51 

willing to see the commercial value of the new invention 
and orders for Bell phones began to pour in upon Hubbard 
by the thousand. Men stood in line to secure agencies. 
Organization and a business manager became essential. 
For this post Hubbard selected a young man named Theo- 
dore N. Vail, the head of the goverriment mail service. He 
took up the work with an enthusiasm that has never failed 
and for nearly half a century has been one of the great cap- 
tains of American industry. 

Edison invented a new transmitter for the Western 
Union which was a vast improvement upon the Bell in- 
strument. This gave the Bell competitors a strong advan- 
tage and enabled them to operate over much longer dis- 
tances. Agents clamored for something equally as good 
and began to lose faith in the Bell Company. The Western 
Union, too, had a network of wires, a host of agents, forty 
millions of capital and great influence. Bell returned from 
Europe to find the affairs of his company in chaos and 
financial success apparently impossible. 

But just at this critical moment there appeared on the 
firing line a young inventor, Clarence Blake, with a trans- 
mitter as good as Edison's. Furthermore he was willing 
to seU his invention to the Bell Company in exchange for 
stock. This placed the company on an equal footing with 
the Western Union as far as equipment was concerned but 
the warfare did not cease. Selecting Elisha Gray who had 
invented a musical telegraph and made application for a 
patent on a telephone which he never perfected, the Western 
Union began suit to estabHsh the rights of Gray. The Bell 
Company fought the case with the ablest legal talent of 
Boston and the Western Union upon the advice of its own 
attorney that it could not prove its case dropped the suit 
and made peace. It was conceded that Bell was the original 



52 The Boys^ Own Book of Great Inventions 

inventor of the telephone and it was agreed that the com- 
panies should divide the business of wire communication 
between them, the Bell Company enjoying a monopoly in 
the telephone field and the Western Union having similar 
privileges in the domain of telegraphy. 

The result of this controversy was to send the Bell stock 
up to $i,ooo a share and the original promoters of the tele- 
phone, selHng their interests, turned the development of the 
business over to other men. Each received a comfortable 
fortune and the reward which was his due. 

The controversy as to who invented the telephone did 
not cease, however, and a bitter war of rival claimants fol- 
lowed. The most important of these contestants was Prof. 
Amos E. Dolbear of Tufts College. Professor Dolbear's 
interest was largely that of the scientific investigator and 
while he undoubtedly did pioneer work on telephone com- 
munication, he certainly did not perfect a practical instru- 
ment as was conclusively shown in the courts. In 1877, 
too, in a letter to Bell, Professor Dolbear accorded to him 
full credit for his great invention. No other patent has 
been so bitterly contested and no one's right to a great in- 
vention more clearly estabHshed than is Bell's to the 
telephone. 

The period immediately following was one of organization 
and development. The first instruments were crude and 
clumsy. The same mechanism served for both receiver 
and transmitter. At telephone stations this important rule 
was usually posted, ''Don't talk with your ear, nor listen 
with your mouth." Telephone switch boards were little 
more than a dream and of the simplest sort. Subscribers 
were Hsted by name and not by number and even when 
New York came to boast 1500 phones its directory con- 
tained no numbers. Calling a subscriber was accomplished 



The Telephone Romance 



SZ 



at first by tapping on the transmitter diaphragm with a 
pencil but this was very uncertain of results and injured 
the instrument. Therefore Watson devised a buzzer and 
finally the magneto call bell. The early exchanges were 




Fig. io. — The first commercial switch board used in New 
Haven, Conn. 

tended by boys and it required a half dozen boys and as 
many minutes on the average to answer a single call. Each 
boy talked at the top of his voice and ran about like mad. 
Pandemonium reigned and one of those early exchanges 
resembled a lunatic asylum let loose. To add to the utter 
distraction of all concerned a great medley of weird noises 
was always present in the telephone receivers at all times 
of day or night. What with tedious delays, impudent boys, 
feeble transmission and the never ceasing bable of noise, 
the telephone-using public did not suffer in those days it 
would be difficult to imagine. 

But better times were to come. The Edison and Blake 
transmitters banished the single instrument for both sending 



54 The Boys' Own Book of Great Inventions 

and receiving and also increased enormously the efficiency 
of transmission. Watson's magneto call bell and J. J. 
Carty's ''bridging" bell by which several subscribers might 
be placed on the same line were immense improvements. 
The expulsion of the boys and the substitution of girls in 
the telephone exchanges was a heavenly innovation to a 
long suffering public. Then came Charles E. Scribner, the 
wizard of the multiple switchboard, which is one of the 
most complex mechanisms of modern invention. Without 
it telephone expansion would have been impossible. In 
the early days it required five minutes to answer a call and 
estabKsh communication, but now, thanks to the magic 
switchboard, it is done in twenty-one seconds. The iron 
wire of high resistance and easily rusted away has been 
replaced with copper made capable of sustaining its own 
weight by a new process for making so-called "hard drawn 
wire." J. J. Carty the first and greatest of telephone en- 
gineers, who by the sheer weight of his own genius has 
developed a new profession, solved among many others the 
problem of underground noises and the maze of overhead 
wires. To eliminate the noises he substituted a return wire 
in place of the earth which had been used to complete the 
circuit in all of the early lines. The result was like magic. 
The unseemly noise disappeared and quiet has since reigned. 
The problem of overhead wires which obscured the sky, 
disfigured a city and broke with the sleet was solved by 
placing them in underground, moisture-proof cables, but 
without for a moment interrupting communication — a 
tremendous piece of engineering work. Then came the 
common battery, also the work of Carty, replacing the 
individual batteries along the line. The electric bell 
for signaling central was replaced with tiny electric 
lights and the device provided by which a subscriber 




Fig. II. — Cortland exchange in 1879. 



The Telephone Romance 55 

may call central by simply removing the receiver from the 
hook. 

The Western Electric Company of Chicago and New 
York, founded in 187 1 by an ex- telegraph operator, Enos M. 
Barton, became the pioneer manufacturer of telephone in- 
struments and in 1880 began work for the Bell Company, a 
work that has grown to immense proportions. The making 
of telephone apparatus is very exacting and every instru- 
ment is subjected to the most rigid inspection. A single 
transmitter receives three hundred examinations and a coin 
box is made to count ten thousand nickles before it is put 
into service. The company now employs thousands of men 
and is the largest manufacturer of telephone apparatus in 
the world. 

The marvelous expansion of the telephone system in less 
than forty years to embrace the whole world in a network 
of wires and cables and making it possible to throw the 
human voice from ocean to ocean is one of the mightiest 
achievements of American genius and enterprise. The 
man who in the early eighties had the vision, the faith and 
the courage to do the pioneer work and carry the develop- 
ment of the business forward to its present gigantic propor- 
tions is Theodore N. Vail who is still in active service. In 
1879 he said, ''I saw that if the telephone could talk one 
mile today, it would be talking a hundred miles tomorrow." 

The Bell Company grew with a rapidity that was amaz- 
ing. Earnings accumulated. The stock began to pay divi- 
dends that mounted into millions but represented only 
legitimate profits. By 1888 it was sending a million mes- 
sages a day. Ten years later it had installed its first million 
telephones. By the close of the century it had strung a 
miUion miles of wire. Exchanges multiplied. In 1892 
New York was talking with Chicago and very shortly 



56 The Boys^ Own Book of Great Inventions 

with Milwaukee, Omaha and other western cities. So was 
Boston. Today there are in the Bell system twenty-one 
million miles of wire connecting nine million telephone sta- 
tions located everywhere throughout the United States and 
binding together in perfect communication one himdred 
milUon people. 

Presently the genie of the telephone system began to 
dream of transcontinental service and then with charac- 
teristic American enterprise the dream became a fact. 
From New York to San Francisco by phone in less than 
one-tenth of a second is only a recent episode in the great 
telephone romance. With Theodore N. Vail and J. J. 
Carty, now General Carty, as leaders, the American Tele- 
phone and Telegraph Company carried its line across the 
plains, over the mountains, through the sage brush and 
down to the Golden Gate, opening transcontinental service 
on January 25, 191 5. The line is 3,390 miles long. There 
are two circuits, each consisting of 6,780 miles of hard 
drawn copper wire. In each circuit mile 870 pounds of 
copper are used and 2,960 tons in the entire line. The 
loading coils for each circuit contain 13,600 miles of fine 
insulated wire 4/1000 of an inch in diameter. The Kne is 
strung on 130,000 poles and crosses thirteen states. The 
voice traveling by air at the slow rate of about 11 60 feet 
per second travels across the continent by telephone in 
about one-fifteenth of a second or at the rate of 56,000 miles 
per second. Marvelous, you say, and so it is. When we 
consider that the very small energy contained in the sound 
waves of the human voice striking upon an iron disc is 
able to set up a train of electric vibrations which pulsating 
along a copper wire in perfect regularity break upon the 
Pacific Coast and reproduce more than three thousand 
miles away the very tone and accent of the speaker's 




Opening transcontinental telephone service, January 25, 191 5. 



The Telephone Romance 57 

voice and all in the fraction of a second, well may we 
marvel. 

But on that memorable afternoon of January 25, 1915, 
Dr. Bell speaking into an exact reproduction of his original 
instrument sent his voice, not a few feet, but 3400 miles 
from ocean to ocean and talked with Mr. Watson in San 
Francisco. Thus the two men who constructed the first 
telephone and sent and received the first message were the 
central figures in this latest achievement of wire communica- 
tion. Imagination, sentiment, history, unrivalled progress, 
are all interwoven in the event. From the skepticism of 
1876 to the crowning success of 191 5, what a glorious chap- 
ter in the romance of American enterprise had been written. 
And yet, as we shall see, the vision of achievement did not 
pass. A still greater accomplishment was yet to come. 

One great invention without which long distance tele- 
phone communication would have been impossible must be 
mentioned. It is the Pupin ''loading" coil devised by Dr. 
Michael I. Pupin of Columbia University. What is called 
the electrical capacity of a long cable becomes so large that 
the alternate charging and discharging of this immense 
condenser, for such it is, so retards the transmission of a 
message, as to make long distance telephony impossible 
without some device to neutralize this capacity effect. To 
overcome this difficulty Professor Pupin used an inductance, 
or so-called loading coil, because he knew that inductance 
had the opposite effect to capacity and would neutralize it. 
These coils are placed every eight miles on the transcon- 
tinental fine and on all other long distance lines. Thus it 
is seen how essential the work of the scientific investigator 
becomes to the commercial expansion of a great enterprise. 

Another man who contributed very much toward the 
success of the transcontinental telephone is Dr. Lee De- 



58 The Boys' Own Book of Great Inventions 

Forest, an American inventor and for two decades one of 
the world's leading investigators in the field of radio com- 
munication. He perfected and sold to the American Tele- 
phone and Telegraph Company the ''Audion Amplifier" 
which, when connected in the line between a transmitter 
and distant receiver, amplifies to a marvelous degree ''the 
voice currents, giving a reproduction of perfect fidelity 
without a trace of lag or distortion, yet with an increase of 
volume, or intensity." A description of this will be given 
under the wireless telephone. 

What the telephone means to the world and has done 
for a quarter of a century and more no man can gauge. It 
spells communication and communication of ideas is the 
basis, of all material intellectual and social progress. The 
great network of wires and cables that tunnel beneath the 
rivers, cross the plains, climb the mountains and span the 
continent bind together in a great fraternity of business 
and social intercourse every part of the nation. Ocean 
sounds to ocean. Isolation has been banished. The farmer 
talks with the distant merchant and has literally brought 
the city markets to his very door. Mine and factory, 
though a thousand miles apart, are on speaking terms. 
Home and ofl5.ce are within sound of each other's voice. 
The great city daihes gather their news by telephone. The 
train dispatchers of the big trunk lines now shuttle to and 
fro the myriad carriers of life and commerce a la, Bell in- 
stead of a la Morse. The Weather Bureau gathers its 
information and sends out its timely warnings for the pro- 
tection of crops and shipping by telephone. The telephone 
is a slave to every director of our big corporations. With- 
out it the wonderful organization and development of 
American industry would have been impossible. The fore- 
man of a distant iron or coal mine sits in his underground 



The Telephone Romance 59 

office and talks with the president of his company on the 
top floor of a New York sky scraper. The passenger in his 
stateroom on an ocean Uner talks direct from pier to home 
or office. So does the occupant of a Pullman in our fast pas- 
senger service. In time of crisis — fire, flood or shipwreck, 
the telephone is the first to the rescue. Although the tele- 
phone has girdled the world, the United States is pre- 
eminently the telephone nation. In the Hudson Terminal 
Building of New York City alone there are more telephones 
than in the kingdoms of Bulgaria and Greece combined. 
The people of the United States talk with each other at 
the rate of more than seven bilHon conversations per year, 
a magnificent tribute to the pioneers and inventors who 
have made the telephone dream come true. 

But it is in time of war that the telephone becomes in- 
dispensable. In the great battle of Mukden in the Russo- 
Japanese war General Oyama of the Japanese army sitting 
ten miles behind the line of attack directed every movement 
of his men by telephone as easily as though he were playing 
a game of chess. In the great World War one of the first acts 
of Great Britain was to establish telephone communication 
between London and the army field headquarters in France, 
then to connect the field headquarters with the divisions at 
the front and to provide temporary telephone lines in the 
combat zone. So well was this done that early in the war 
Sir John French from his home near Hyde Park, London, 
for three days directed the field operations in Flanders. 

Close upon the heels of the army follow the telephone 
engineers and linemen. A cable drum mounted upon a 
limber unreels the wire which is hidden beside the road or 
strung on Hght poles. All wires from a given front lead 
to a central station behind the lines which consists of a 
switchboard carried on a wagon. Since the switchboard 



6o The Boys^ Own Book of Great Inventions 

can be operated without removal from the wagon the 
central office may be moved quickly to any point of the 
field. 

Orders are given, cannon fired and army corps manipu- 
lated all by telephone. Scouts and spies move forward 
carrying portable telephones and quickly flash back to 
headquarters valuable information. Observation balloons 
carrying an officer with a telephone and paying out wire as 
they ascend give quick reports of enemy movements. Every 
part of the trenches is connected with every other part and . 
with headquarters by telephone. The telephone outposts 
and the men who operate them figure in the most brilliant 
exploits of modern warfare and when the history of this 
great struggle comes to be written the heroism of the tele- 
phone branch of the signal corps will loom large in its pages. 

Thus in peace and war the telephone has become a mighty 
servant of the race. What a tremendous echo now re- 
sounds from all the earth in response to the first feeble 
message from Bell to Watson in the Boston attic on that 
ever- to-be-remembered tenth of March, 1876. 




Fig. 12.— First universal switch board invented bv Charles E. Scribner. 



Chapter IV 

PRINCIPLES OF THE TELEPHONE 

The Theory. — The operation of the telephone in repro- 
ducing sound waves will become clear from a consideration 
of Fig. 13 which represents a very simple form. Two soft 
iron discs, E and E', are mounted close to the ends of two 




SSS3N 



r^ 'VZTZV. 



E' 



Fig. 13. 

permanent bar magnets, M and M', upon which are placed 
spools of fine wire. One end of each spool of wire is joined 
to a line wire and the other is attached to a copper plate 
buried in the ground. Now a bar magnet is surrounded 
at all times by a multitude of invisible Hnes of force pass- 
ing from the north pole of the magnet through the air to 
the south pole and back to the north pole. These lines 
of force constitute the magnetic field and upon them de- 
pend all the properties of the magnet. 

The fundamental principle of the telephone is that of 
induction, which may be stated as follows : Whenever mag- 

6i 



62 The Boys^ Own Book of Great Inventions 

netic lines of force are made to cut across a conductor an 
electric current is induced in that conductor. Soft iron 
has a great attraction for Hues of force. Therefore in 
passing from one end of the magnet to the other these lines 
of force surge into and out of the soft iron disc. Now when 
one speaks against the soft iron disc, the condensations 
and rarefactions of the sound waves produced by the voice 
strike upon the disc and cause it to vibrate. A condensation 
is a compression in the air in which the pressure is sHghtly 
increased and this is immediately followed by a rarefac- 
tion in which the particles of air are less dense than usual 
and under diminished pressure. These condensations and 
rarefactions which correspond to the crests and troughs 
of water waves follow each other in regular order and beat 
upon the iron disc Hke the breakers upon the sea shore. 
As a condensation strikes the disc the soft iron is forced 
a little nearer to the end of the magnet and the lines of 
force surge into it still more and in doing so cut across the 
fine wire wound on the spool. According to the principle 
of induction this must induce a current in the wire which 
will travel over the Kne and about the other spool of wire 
down to the earth and back to the starting point. Then 
since a current bearing conductor always has a magnetic 
field of its own these lines of force from the induced current 
will strengthen the field of the opposite magnet and cause 
it to attract its soft iron disc at that end with an increased 
force thus drawing it in. As the rarefaction, consisting 
of air at diminished pressure strikes the disc, the pressure 
being removed, it moves away from the end of the magnet 
sHghtly and the lines of force surge out of the soft iron disc, 
thus cutting across the spool of wire in the opposite direc- 
tion and inducing a current that will travel through the 
circuit in the opposite direction. The field of force of this 



Principles of the Telephone 



63 



second induced current will of course have an effect oppo- 
site to that of the former and the pull on the disc at the 
other end of the line will be weakened causing it to spring 
outward. Thus it will be seen that these condensations 
and rarefactions striking upon one disc will, because of 
the currents which they induce in the Une, make the op- 
posite disc vibrate in perfect unison and therefore produce 
sound waves at that end of the line exactly similar to the 
original waves. Proof of this lies in the fact that we readily 
recognize a friend's voice over the phone. Now this was 
in principle the sort of a telephone with which Bell startled 




Fig. 14. 

the world at the Centennial Exposition in 1876. We can 
understand now how Watson accidentally sent the first 
audible sound over the line on that hot afternoon of June 2, 
1875. When the contact points of his transmitter fused 
together, thus closing the circuit, Watson by plucking the 
reed made it vibrate just as a telephone transmitter does 
and induced currents which caused the reed at the re- 
ceiving end to vibrate in unison and produce a sound. 

The Receiver. — A telephone receiver as shown in Fig. 14 
consists of a permanent horseshoe magnet with a spool 



64 



The Boys' Own Book of Great Inventions 



of fine wire at each pole. The two spools are connected in 
series with each other and with the line. In front of the 
poles of the magnet is mounted a soft iron disc. Its action 
is exactly like that of the apparatus already described and 
in the original telephone lines this same form of instrument 
acted as both transmitter and receiver after the manner of 
a speaking tube. 

An Experimental Line. — For short distances a very good 
telephone line may be made by cormecting in series two 




Fig. 15. — A microphone. 

receivers. Use about number 14 copper wire for the line 
and ground one terminal at each end by connecting to a 
gas or water pipe. To insure good results it may some- 
times be found necessary to use a second wire for the re- 
turn instead of the ground. It was with such a line as 
this that Bell and Watson did their first real reciprocal 
telephoning from Cambridge to Boston Oct. 9, 1876. 
The Transmitter. — It will be seen now that the problem 



Principles of the Telephone 



65 



of inventing a separate transmitter consisted in devising a 
mechanism that would enable the sound waves to produce 
a variation of the magnetic lines of force, thus inducing the 
talking currents. The principle of the transmitter invented 
by Edison and in modified form by Blake is well illustrated 
in the simple microphone. 

Points P and P^ in Fig. 15 are carbon buttons, one being 
fastened to a strip of pine wood sounding board and the 
other to a brass spring which holds the two buttons in 
contact. The two buttons are connected in series with a 
dry cell and a telephone receiver as shown, the receiver 
being placed at a considerable distance away. Now if a 
watch be placed on the base or a faint sound be made by 
the scratching of a pin 
the sound waves pro- 
duced will vary the re- 
sistance between the 
very sensitive contact 
points of the carbon but- 
tons and therefore alter- 
nately increase and de- 
crease the battery current 
which flows through the 
telephone receiver. As 
already explained this 
will cause the iron disc of 
the receiver to vibrate 
and repeat the sound with great distinctness. Any boy 
can readily make such a microphone and test this principle 
for himself. 

Blake's transmitter made use of two carbon pencils as 
in the microphone. One of these pencils is fastened to the 
vibrating iron disc and the two are placed in series with 




Fig. 16. 



66 



The Boys^ Own Book of Great Inventions 



the battery current. The modern transmitter as developed 
by the Western Electric Company is shown in Fig. i6 and 
as will be seen it contains a small box of granular carbon B 
through which the battery current must pass. The alum- 
imum diaphragm D connecting with one of the battery 
wires is in contact with one side of this box of granular 
carbon and as sound waves strike upon it is set into vibra- 
tion alternately exerting pressure upon the carbon and 
then releasing the pressure. This action in turn decreases 
and increases the resistance of the battery circuit thus 
causing first more and then less current to flow. 

The Line. — ^The arrangement of both transmitter and 
receiver for two stations is shown in Fig. 17. Here as will 



(I:=J==r: 




Fig. 17. 

be seen there are two circuits, a primary and a secondary. 
In the primary circuit are placed the transmitter and 
batteries, in the secondary the receivers in series with the 
Kne. The coils of wire at P and S are wound upon a soft 
iron core and constitute a small induction coil. The pri- 
mary P consists of comparatively few turns of coarse in- 
sulated wire and the secondary S of a large number of turns 
of fine wire. In practice the secondary is wound on a 



Principles of the Telephone 67 

spool surrounding the primary. Now as the condensation 
and rarefactions of the sound waves strike upon the alum- 
inum disc of the transmitter the disc is set into vibration 
and as already explained alternately increases and de- 
creases the primary current. This variation of current 
also produces a corresponding increase and decrease in 
the strength of the magnetic field in the primary of the 
induction coil, the lines of force surging outward and in- 
ward across the secondary and inducing talking currents 
in the line. These talking currents pass through the re- 
ceivers increasing and decreasing the fields of the per- 
manent magnets in them and causing their soft iron discs 
to vibrate in unison with the transmitter disc. The result 
is, as all the world knows, the production of sound waves 
which exactly dupHcates the speaker's voice. Such a sys- 
tem as this with batteries at each subscriber's phone is 
the one in common use among the local lines of country 
districts. 

The Central Station System. — In the modern central 
station system the individual batteries have been discon- 
tinued and the primary current is supplied by a battery of 
about 24 volts at the central station. The essential parts 
of such a system are shown in Fig. 18. As the subscriber 
removes the receiver from the hook the line circuit is closed 
at contact D and the current flows from battery B in the 
central station through the electro-magnet E. This elec- 
tromagnet closes the small shunt circuit through the glow 
lamp L which is directly in front of the operator. Upon 
seeing this signal the operator immediately inserts the 
answering plug P into the subscriber's jack J, and presses 
the listening key K which connects her own receiver with 
the line. The subscriber gives the number which he wants 
and the operator inserts the calling plug into the jack of 



68 



The Boys' Own Booh of Great Inventions 



the desired line at the same time pressing the ringing key K' 
which throws an alternating current from the magneto M 
onto the line. When the subscriber being called answers, 
the operator throws out her own listening key and the 




.-J Z^ZZl 



Fig. i8. 

two parties are directly connected. As the subscribers 
hang up their phones a second lamp not shown in the dia- 
gram lights signifying that the conversation is ended. The 
operator then immediately removes the plugs and the 
lines are disconnected. 

It will be observed that the first signal lamp to light 
goes out on the insertion of the operator's plug by opening 
the contact points at A. Also the first subscriber is mo- 
mentarily cut off when the ringing key is pressed by open- 
ing the contact points at C. Otherwise the first subscriber's 
bell would ring too. 

The call bells are polarized bells which respond to an 
alternating current but not to direct current. The con- 
denser also breaks the circuit for a direct current but not 
for an alternating current. 

A Simple Telephone. — ^A very simple but very sensitive 
telephone can be made by any boy as follows: 

To a piece of board about five inches long, four inches 
wide and a quarter of an inch think mounted on a wooden 
base fasten two vertical carbons about three-sixteenths 
of an inch in diameter. Small claw tacks may be used 
for fastening the carbons. Place a hook at the middle and 



Principles of tlte Telephone 



69 



top of the board and on this hang a piece of light soft wood 
carrying another carbon placed crosswise. This carbon 
should rest Hghtly against the two vertical carbons. This 
combination constitutes a very sensitive microphone 
transmitter. Now attach wires to the vertical carbons 
and carrying them through holes in the upright board 
connect the carbons in series with two dry cells and a 




Fig. 19. — A simple telephone. 

telephone receiver. The latter may be placed at distances 
of several hundred feet from the transmitter. The carbon 
placed crosswise and resting against the vertical carbons 
makes a poor contact in the circuit and as the sound vibra- 
tions strike upon the mouth piece the alternate increase 
and decrease in pressure which results varies the current 
flowing through tne receiver and causes its iron disc to 
vibrate, reproducing the sound. 



70 The Boys^ Own Book of Great Inventions 

A Home-make Telephone. — ^Any boy may have the pleas- 
ure of constructing a pair of simple telephone instnmients 
and building an experimental line similar to Bell's first 
line with very little work and expense. 

First secure an extra strong steel magnet about 5 inches 
long and preferably round. Over one end slip a piece of 
stock-fibre tubing and two tight fitting washers of the same 
material to serve as a spool. On this wind 200 turns of 
No. 26 double covered copper wire. Mount the magnet 
and spool on a base as shown in the diagram. The magnet 
should fit loosely enough in the upright to permit of moving 
it backward or forward in making adjustments. Now 
from any telephone manufacturing company or electrical 
store obtain two soft iron discs such as are used in telephone 





itl 






OI&C 1 


Z±l 








t^ ~ 




y 


V///y>//yry 





K\\\S\\\S\\\SS\^ 



-sorr IRON 

013C 



Fig. 20. — An experimental line. 

receivers. Cut a circular hole in the end of a box about 
4 inches high and 6 inches long and cover it with the soft 
iron disc. Mount the box over the magnet bringing the 
disc very close to the end of the magnet but not quite 
touching it. Using about No. 14 copper wire for the *Mine'' 
connect this instrument with an exactly similar one some 
distance away. There should be a second return wire 
rather than using the ground for the return. 

Making use of each instrmnent as both transmitter and 
receiver, just as Bell did, test the talking quaHties of your 
line. You will be surprised at the results. In order to 
secure the best results, however, it will be necessary to 
adjust very carefully the distance between the iron disc 
and the magnet. 



Principles of tlie Telephone 71 

The operation of this line is exactly the same as that 
of any other telephone line. As sound waves strike upon 
the disc of one instrument causing it to vibrate a varying 
magnetic field of force is made to cut across the turns of 
wire on the spool. This cutting of the lines of force induces 
a current in the wire which traveling about the other mag- 
net alternately increases and decreases the pull on the 
disc throwing it into vibration and reproducing sound waves 
identical with those spoken into the transmitter. 

Such a line may be constructed from one house to another 
or from garret to basement and both pleasure and instruc- 
tion derived from its use. 



Chapter V 
THE TRIUMPH OF WIRELESS 

The world had scarcely mastered the awe with which 
it regarded the telephone when the wizardry of wireless 
fairly swept it off its feet. If sending the voice over an 
electrified wire is awe inspiring, and it surely is, what shall 
we say of this latest mastery of the realms of space without 
the aid of any material medium whatever? Truly, this 
signaling for vast distances with only the boundless ether 
to conduct our message seems little short of magic. The 
rapid progress made, too, by these genie of the radio art 
has appeared to the populace like the triimiphant march of 
a group of giants moving forward in seven league boots. 
One success has quickly followed another until from signal- 
ing a few feet without wires we may now wireless a message 
a quarter of the distance about the globe. And what 
seems today the limit of possibility may be but a stepping 
stone to a greater success tomorrow. 

Although Guglielmo Marconi is the master genius whose 
faith and vision have led to the triimiph of wireless com- 
munication, it is equally true that many other pioneers 
of science have contributed to this great achievement. 
Probably one of the first to make use of the water as a 
conducting mediimi for the transmission of telegraphic 
messages was Morse during those dark days of patient 
waiting for the assembling of a Congress favorable to his 
great idea. As shown in the diagram, he submerged plates 
on one side of a river at a distance of about three miles 

72 



TJie Triumph of Wireless 



73 



apart and connected them in series with batteries and a 
key. On the opposite shore he placed similar plates and 
in circuit with them a sensitive galvonometer. When 
the key was pressed a current flowed from the batteries 
to El and here it divided, part going to E2 and back to the 




z,^ 



^. 



Fig. 21. — Morse's "wireless" system. 



battery and the remainder passing over to E3, through 
the galvonometer and back to the battery by E4 and E2. 
The galvonometer recorded the current and thus signaling 
by water connection became possible. Although not wire- 
less as we understand it today, yet this was to some extent 



74 The Boys^ Own Book of Great Inventions 

sending messages without wires and as we shall see had 
several important applications a half century later. 

Nothing further of importance occurred in the develop- 
ment of wireless telegraphy until after the invention of 
the telephone. The telephone receiver gave a wonder- 
fully sensitive instnunent for the detecting of very small 
electric currents. In 1880, Professor Trowbridge of Har- 
vard University demonstrated that if the terminals of an 
alternating current dynamo were grounded electric vibra- 
tions would spread through the earth and might be de- 
tected by grounding the terminals of a telephone circuit. 
He varied the experiment by substituting an induction 
coil for the dynamo and grounding the secondary terminals. 
The currents thus transmitted were so feeble for anything 
but short distances, however, that no practical results 
came from these experiments. They were of immense 
scientific interest, though, and furnished material for 
those who were to foUow. 

Professor Trowbridge also worked out a plan for trans- 
atlantic communication using the water as a conductor 
as Morse had done a generation before. But the practical 
difficulties and the cost of operation seemed to prohibit 
this method and the idea was abandoned. Trowbridge 
suggested a similar plan for wireless communication be- 
tween ships at sea and Dr. Bell a few years later suc- 
ceeded in accomplishing this for ships half a mile apart. 
The indefatigable Trowbridge still persisting in his efforts 
discovered that if a coil of wire be raised in the air and a 
current sent through it, there would be induced in a similar 
coil facing it and at some distance away currents that 
might be detected with a telephone receiver. To trans- 
mit for even short distances, however, required enormous 
coils and large currents making this method impossible. 



The Triumph of Wireless 75 

Trowbridge was approaching the real solution of the prob- 
lem and will always receive large credit for the pioneer 
work which he did. 

Professor Dolbear, who had previously done work on 
the telephone, was one of the early investigators of wireless 
communication. He used an induction coil and sent 
powerful currents into the earth being able to detect them 
at a distance by means of a telephone receiver as Trow- 
bridge had done. He took out a patent on aerial antennae, 
and in 1879 invented a static telephone which in a very 
remarkable way anticipated wireless telegraphy. Professor 
Dolbear, however, did not develop a working system of 
wireless. He was rather the prophet who caught the vision 
of a great achievement and had supreme faith in its ulti- 
mate triumph but did not contribute the painstaking 
work and drudgery essential to practical success. 

Another very interesting and it would seem practical 
application of wireless was made by Edison in 1885. He 
patented a system which enabled moving trains to send 
and receive messages at any part of the line. Small aerials 
eighteen inches high to which was connected sending ap- 
paratus were placed on the tops of the cars and grounded 
through the steel framework and rails. The ether waves 
sent out from these aerials induced currents in the telegraph 
wires running parallel with the track, which traveled to 
the stations along the Kne. The speed of the train did not 
interfere in the sHghtest with the transmission and the 
system was in every way a success. It failed though of 
any extensive commercial appHcation and Edison turned 
to other lines of investigation. 

Now the scene shifts to Europe and America was to be 
denied the honor of inventing and developing wireless 
as it had done the telegraph and the telephone. The next 



76 The Boys^ Own Book of Great Inventions 

man to figure prominently in wireless work was Sir William 
H. Preece, Engineer-in-Chief of the Postal Telegraphs of 
England. Adopting the methods of Morse and Trowbridge, 
Preece early in the 80' s succeeded in establishing wireless 
communication between the Isle of Wight and the main- 
land of England when the cable between the two places 
had been put out of commission. Erecting parallel circuits 
on the opposite shores with their terminals submerged in 
water, he placed batteries and a telegraph key together 
with a telephone receiver in each circuit with perfectly 
satisfactory results. By 1892, Sir William Preece and 
A. W. Heaviside, were signaling across a space of ten miles 
by means of parallel telegraph lines. Mr. Heaviside, too, 
was able to commmiicate with mines nearly four hundred 
feet deep by laying wires on the ground above and ar- 
ranging similar circuits in the mine. About this time 
communication was established with the Hght station on 
Fastnet Rock seven miles off the coast of Ireland. Owing 
to the exposed position of this station and the extreme 
violence of the waves cable communication was constantly 
interrupted. To remedy this the cable was cut not far 
from shore and anchored to the bottom. Telegraph wires 
were submerged at either end and service was maintained 
without difficulty. 

But no one up to this time had really grasped the theory 
of wireless communication. Many experimentors had 
demonstrated its possibility and were groping in the dark, 
as it were, for better and more efficient means. It re- 
mained for Heinrich Hertz, a yoimg German scientist, 
professor of physics at Carlsruhe and former pupil of 
Helmholtz, in that series of now classic experiments, to 
demonstrate the possibility of signalling through the all 
pervading ether of space. Clerk-Maxwell, the great Eng- 



The Triumph of Wireless 



77 



lish physicist, had in 1864 shown theoretically that light 
is due to electro-magnetic vibrations, but being a mathe- 
matician rather than a scientific experimenter, he was un- 
able to prove his theory. In 1886, in his epoch making 





• » 




INDUCXION COIL. 



Fig. 22. — ^Apparatus for demonstrating the Hertzian waves. 

discovery that there are ether waves possessing all the 
properties of light waves but of much greater length and 
lower pitch, Hertz confirmed the prophecy of Maxwell 
and set at work a host of experimenters in this new and 
delightful field of scientific research. 
Hertz carried out his experiments with an induction 



78 The Boys^ Own Book of Great Inventions 

coil, what we shoiild now call a crude aerial and a resonator. 
An induction coil, explained in another portion of this 
book, is a piece of apparatus for changiQg currents of low 
voltage and relatively large quantity into high voltage 
and small quantity. There are two circuits, a primary 
and a secondary, the latter containing a gap across which 
a powerful spark discharge occurs when the primary cir- 
cuit is broken. Leaving a small gap between the terminals 
of the secondary, Hertz connected to each side of the gap 
copper rods about twelve inches long and terminating in 
plates of brass or sheet zinc fifteen inches square. As 
these plates become highly charged just previously to the 
spark discharge, a severe strain in the ether is set up be- 
tween and about them and when the air gap breaks down 
and the discharge occurs this ether strain is transformed 
into a train of electromagnetic waves which spread out- 
ward in all directions. The resonator is a device for de- 
tecting the presence of these electromagnetic waves. The 
one used by Hertz in these first crude experiments con- 
sisted of a stout copper wire circle of twelve inches radius 
with a very small spark gap in the circle. Now when he 
held this circle parallel to the spark gap of the induction 
coil and its plates, he obtained minute sparks across the 
resonator gap of the circle. A simple thing to do it may 
seem, and yet in this discovery lay the germ of all the 
marvelous wireless work that has followed. 

Hertz soon foimd that he could time his resonator. He 
made the spark gap adjustable and by changing the width 
of it discovered that there was a certain length at which 
the spark was brightest. He also found that there was a 
certaiQ position of the plane of the resonator in which the 
result was best and therefore concluded that the ether 
waves traveled in a particular direction. This tuning of 



The Triumph of Wireless 79 

the resonator is exactly similar to the sympathetic vibra- 
tions observed in musical instruments of the same pitch 
and had a tremendous influence on the later development 
of radio communication. 

By placing his oscillator, as he called the induction coil 
and plates, and his resonator in paraboHc mirrors he was 
able to prove that these electromagnetic waves could be 
reflected, refracted and polarized and therefore possessed 
all the properties of hght and radiant heat waves. By a 
method exactly similar to that by which we measure the 
length of a sound wave. Hertz was able to measure the 
length of the ether waves finding them to be about 100 feet 
and their velocity therefore 186,000 miles per second, or 
identical with that of light. No further proof was necessary 
to estabHsh the fact that Hght waves are also electromag- 
netic vibrations, differing from electrical vibrations simply 
in wave length. It was a brilliant discovery and led to 
magnificent results. 

Even earlier than this Sir Oliver Lodge had performed 
an experiment with Ley den jars very similar to that of 
Hertz. A Leyden jar is a condenser made by coating a 
glass jar both inside and out with tin foil for about two- 
thirds the way from the bottom to the top and covering 
with an insulator through which is thrust a metal rod in 
contact with the inside foil and terminating in a knob 
above. Sir Oliver Lodge arranged two jars as shown in 
the diagram and connected one of them to an induction 
coil or the terminals of a static machine. Between the 
knobs of this jar sparks would pass and the electromag- 
netic waves striking upon the other jar produced small 
sparks at its terminals. This was possible, however, only 
when the two jars were tuned to the same pitch and to 
accomplish this a sHding contact CD was provided for the 



8o 



The Boys^ Own Book of Great Inventions 



rectangular conductor of the second jar. By sliding this 
along until the areas of the two sets of conducting surfaces 
were the same the point of ^'syntony" was reached and 
the two circuits were in tune. But it did not occur to 




Fig. 23. — Apparatus used by Sir Oliver Lodge. 

Lodge that this simple experiment might be made the 
basis of wireless telegraphy and as he said himseK later 
he did not see the necessity for wireless conmumication 
with wire telegraphy and telephony developed to so high a 
state of perfection. 

In 1890, Professor E. Branly of Paris discovered, or 
rather rediscovered, the principle of the coherer, a sensitive 
detector of electric waves, without which the early practi- 
cal development of wireless work would have been impossi- 
ble. Professor Branly foimd that if a small glass tube 
loosely filled with metal filings were placed in circuit with 
a battery and electric bell it would not conduct sufficient 



The Triumph of Wireless 8i 

current to ring the bell. When, however, Hertzian waves 
fell upon the metal particles he found that they would 
cohere, or arrange themselves in a path of such small re- 
sistance as to allow the current to flow and ring the bell. 
This suppHed just the missing link necessary to further 
progress. One of the first to utilize this new discovery was 
Professor A. Popoff of Russia. He made a coherer as 
resonator, running a wire leading from the fihngs high into 
the air and was able to detect the electromagnetic waves 
from Ughtning discharges. 

Marconi and His Work. — Much preliminary work had 
now been done and the stage was set for the man of genius 
who combining the vision of the seer with the mechanical 
skill of a master workman should be able to bring his 
dreams to pass. Such a man, or rather boy, for such he 
was at that time, was Guglielmo Marconi. Marconi, the 
youth, saw the great possibihties of wireless commmiica- 
tion and with the clear insight of genius perceived that 
the discovery of the Hertzian waves opened a door to their 
realization. 

Marconi was born on April 25, 1874, at Villa Griflone 
near Bologna, Italy. His father was an Italian and his 
mother an Irishwoman. He attended both Italian and 
English schools, learning to speak both languages fluently. 
He early showed great aptitude for scientific pursuits and 
under his Italian master. Professor Righi, an investigator 
of some note, he learned of the Hertzian waves and what 
had been done up to that time. Becoming impatient with 
the slow progress made by the great scientists of the world 
in their well equipped laboratories, Marconi set out to 
experiment for himself. This was about 1894 and we 
must remember that at that time no real practical work 
with a view to telegraphing through the ether had been 



82 The Boys^ Own Book of Great Inventions 

done. The so-called methods of Trowbridge, Edison and 
Preece had been based upon conduction and induction, 
making use of the earth or water and had not called into 
full service the electromagnetic waves of Hertz. But 
Marconi with only a knowledge of the Hertzian discovery 
began a work or true research, the brilliant results of which 
very shortly startled the world. 

Marconi began his experiments on his father's farm. He 
employed an induction coil and oscillator similar to the 
one used by Hertz but he made a new departure which 
proved to be his first great contribution to the new science 
of radio communication. This consisted in grounding one 
terminal of the induction coil and in connecting the other 
to a wire which stretched upward into the air. By so doing 
Marconi increased many times the capacity of his oscilla- 
tor to produce and radiate electromagnetic waves. He 
also used a similar aerial for receiver and in a short time 
was able to transmit signals corresponding to the Morse 
code across a distance of a few hundred feet. 

He soon saw that the critical part of his apparatus was 
the receiver and very shortly adopted the Branly coherer. 
He made important improvements in this and increased 
its sensitiveness wonderfully. For the metal filings he 
used nickel powder mixed with a small quantity of silver. 
These he inserted between silver plugs in a small glass 
tube. The plugs were placed about a millimeter apart 
and platinum wires were soldered to them. It required a 
good deal of experimenting to determine just the right 
quantity of powder and the proper pressure and distance 
between the plugs in order to secure the required degree 
of sensitiveness. Now Branly had discovered that after 
the filings had been made to cohere by the passage of a 
train of electromagnetic waves they could be placed in 



The Triumph of Wireless 



S3 



the non-conducting state again by tapping the glass tube. 
Therefore, Marconi devised an automatic tapper or deco- 
herer, as it was called, which after the passage of each 
wave train gave the tube a Hght blow and jarred apart 



SOUNDER 




RELAY r 



^-choi^e: coiu 



I 
I 



ao" 



HM 



COHERCR 
I 



t 



^ 



CHO^NCCOIL- 



>—i 



O&COhtRER-i 




s 



I : 



\zrj 



Fig. 24. — Marconi's early receiving set. 

the metal filings. In the receiving aerial Marconi inserted 
his coherer and in circuit with it a battery and relay which 
just as in the ordinary telegraph receiving set makes and 
breaks a local circuit which operates the heavy sounder. 
When Marconi pressed the key of his transmitter a spark 



84 



The Boys^ Own Book of Great Inventions 



jumped across the gap of the induction coil and the train 
of electromagnetic waves proceeding from the sending 
aerial and moving through the ether were caught by the 
receiving aerial, passed through the coherer and down to 
the earth. This passage of the wave train through the 



SPARK GAP 




INDUCTION 
COIU 



Fig. 25,— The Marconi sending apparatus. 

coherer made a conductor of the metal fiHngs thus closing 
the relay circuit which in turn operated the local circuit 
and sounder. At the same time current flowing through 
a shunt circuit caused the decoherer to disarrange the metal 
filings and thus break the relay and local circuits. By 
holding the transmitter key for short or long periods the 



The Triumph of Wireless 85 

resulting wave trains could be made correspondingly short 
or long and to give rise to the dots and dashes of the Morse 
code. Only a small portion of the ether waves sent out 
by the transmitter aerial were caught by the receiving 
aerial and were therefore too weak to operate a receiving 
mechanism themselves. The early transmitting and re- 
ceiving outfits of Marconi will become clear from a con- 
sideration of the accompanying figures. 

One important discovery made by Marconi early in his 
work was that the height of the aerial greatly affected the 
range of his sending station, the higher the aerial being 
the greater the range. He continued to experiment and 
improve his apparatus until in 1896 he was sending mes- 
sages over distances of several miles. In that year he 
went to England with his wireless system, submitting it 
to Sir William Preece, who was at that time in charge of 
the Postal Telegraph system of England. Preece, who 
had also experimented along these same lines, received 
him cordially and gave hun every assistance possible. 
A short line set up in the Post Office Building in London 
worked with perfect success and stations two miles apart 
were erected outside the city with equally good results. 
In the following year Marconi set up a station on the Isle 
of Wight and maintained communication with the main- 
land. Returning to Italy he secured the use of a warship 
for his tests and sent messages for considerable distances 
from ship to shore. In 1898, his wireless outfit was used 
to send news of the annual Kingstown regatta to a Dublin 
paper, the apparatus being placed on board a steamer 
which followed the yachts. 

Very soon Marconi had established wireless communi- 
cation across the Channel between England and France. 
Channel steamers were equipped with wireless and its 



86 The Boys^ Own Book of Great Inventions 

utility was quickly established by the service one of these 
boats was able to render through its aid to a ship in distress 
off a rocky portion of the North Sea coast. Being unable 
to go in safety to the rescue of the crew of the imperiled 
ship a wireless message to the land station brought timely 
assistance. Light-ships were suppHed with wireless equip- 
ment and its great value in this field was early recognized. 
The British Admirality equipped its battleships with wire- 
less outfits and in a sham battle completely demonstrated 
its great usefulness in naval warfare. 

But the greatest triimaph was yet to come. Marconi 
was able to signal over the greater part of eastern Europe 
and his next objective was to transmit messages across 
the Atlantic. It is interesting to note that in this early 
pioneer work Marconi had not been compelled as most 
inventors are to struggle against poverty and adversity. 
Just as in the case of Morse and Bell there were plenty to 
ridicule his early claims, but one success so rapidly fol- 
lowed another that the scoffers did not have long to enjoy 
their sacred prerogatives. His father supplied the funds 
for his early work and after demonstrating its great utiKty 
the British Admirality paid him $100,000 for the use of 
his invention in the navy. Other countries paid him similar 
royalties and there were left the tremendous commercial 
possibiKties which have been a still richer reward. 

For the purpose of signaling across the Atlantic Marconi 
estabHshed the famous Poldhu Station at Cornwall, Eng- 
land. Instead of using a single aerial or antenna, as he 
called it, he erected a large number of tall masts and con- 
nected them with wires strung from mast to mast. The 
batteries and induction coil which had served as transmitter 
in all his early work were replaced with powerful dynamos 
and a huge transformer. In December, 1901, Marconi 



The Triumph of Wireless 87 

crossed to America and at St. Johns, Newfoundland, with 
immense kites for an aerial he waited in perfect confidence 
for the prearranged signal. It had been agreed before 
leaving Cornwall that at intervals of three minutes between 
the hours of three o'clock and six o'clock, English time, 
the Poldhu station should send three dots, the signal for 
the letter S in the Morse code. Because of its greater 
sensitiveness, Marconi substituted a telephone receiver 
for the relay and sounder and with this at his ear waited 
patiently on Dec. 12th for the signal. He did not have 
long to wait for presently three unmistakable clicks sounded 
in the receiver and Marconi knew that transatlantic wire- 
less was not merely a possibility but a demonstrated fact. 

Marconi returned to England and a little later in a second 
trip to America on the steamship Philadelphia kept in 
commimication with the Poldhu station for a distance of 
150 miles and was able to receive messages at a distance 
of 2000 miles. Wireless telegraphy was now firmly es- 
tablished and the time had arrived for expansion and 
commercial development. 

In the mean time experimenters in every country had 
been at work and naval and merchant vessels were being 
equipped with wireless apparatus. Ship-to-ship and ship- 
to-shore communication became the fad of the hour. Wire- 
less messages from transatlantic liners for two days after 
leaving port were regularly received. As the telephone 
had banished the by-places of the continent so the new- 
born wireless was destined to banish the isolation of the 
sea. Surely the world is shriveling in size and even now 
seems like a pigmy in comparison to the great unknown 
that Colmnbus set out to explore. 

Wireless telegraphy rapidly demonstrated its usefulness. 
The sea is its pre-eminent domain and here it became 



88 The Boys^ Own Book of Great Inventions 

supreme. Numerous rescues of shipwrecked vessels, es- 
pecially in the cases of the Republic in 1903, and later of 
the Titanic, proved its worth. The United States Govern- 
ment as well as foreign goveriunents early passed laws 
requiring wireless equipment on all Hners engaged in pas- 
senger service. The next great contribution of Marconi 
was his system of tuning wireless transmitters and re- 
ceivers to a definite pitch so that no matter how many 
messages might be traversing the ether at the same time 
a given receiving set would respond only to waves of a 
certain length. The method by which this is done will be 
explained later, but it can be clearly seen that without 
such means of timing every receiver would record a perfect 
jumble of signals and intelligible communication would 
be impossible. 

Later Development. — ^A large number of inventors and 
scientists have since contributed to the development of 
wireless receiving and sending mechanisms. The whole 
practice of wireless has been revolutionized. Adjustable 
aerials have replaced fixed aerials. For the induction coil 
and battery circuit have been substituted the high fre- 
quency alternating current generator and transformer. 
Condensers and oscillation transformers have been added 
to the transmitting apparatus. In the receiving set the 
coherer and Morse instruments have given way to a more 
sensitive type of detector and the telephone receiver. Am- 
plifiers for the feeble electromagnetic waves which distant, 
aerials are able to gather have increased enormously the 
range of transmission and reception. The dots and dashes 
similar to those of the Morse instnmient are now produced 
in the telephone receiver as a series of musical notes of 
short and long duration. Among American inventors who 
have contributed much to the development of wireless 



The Triumph of Wireless 89 

systems are Dr. Lee DeForest and Professor Fessenden, 
both of whom are world leaders in the science of wireless 
communication. 

The wildest flights of fancy of the early pioneers have 
been more than reaHzed in the wonderful applications of 
wireless telegraphy in the commercial, naval and military 
affairs of all the great nations of the earth. As already 
stated its use is indispensable on ship board and so numerous 
and powerful are shore stations that at no time during an 
ocean voyage are travelers out of touch with land. But it 
is in the great European War that wireless has demon- 
strated its wide range of usefulness. Naval ships have 
been controlled by wireless, including the German U-boats. 
Millions of dollars and thousands of Hves have been saved 
by the system of radio communication adopted by all 
nations. Aircraft have been equipped with wireless sets 
making use of the metal frame for a ground and a trailing 
wire paid out from a reel for an aerial. These sets have 
a sending range of from 30 to 35 miles, but because of the 
great noise and vibration of the engine, receiving is ex- 
tremely difi&cult. Aside from scouting their chief use is to 
direct artillery fire. The Zeppelins are able to carry more 
powerful apparatus having a range of from 60 to 120 miles. 

The armies in the field carry portable wireless outfits. 
These are usually mounted on two wagons, one of which 
carries the generator and the other the wireless apparatus. 
In rough countries the outfit is carried on mule-back. 
Within five minutes the aerial can be erected and signalling 
begim. Wireless is employed very largely for trench war- 
fare communication. 

Early in the war when Germany was cut off from the 
outside world she established wireless communication and 
from the powerful station at Nauen, near Berlin, has sent 



9© The Boys^ Own Book of Great Inventions 

out her messages to the entire neutral and belligerent world. 
No nation could censor them and her own version of the 
war could be given the utmost publicity. The Allied 
powers kept in commimication with each other and from 
the powerful Eifel Tower station in Paris the Western 
front was kept in touch with Russia and the East. 

At the opening of the great War in 19 14, there were 
scattered throughout the world about 700 land stations 
and 4500 ship stations. Since then these numbers have 
been greatly increased and when the war is over there 
will be put into operation a chain of wireless stations en- 
circling the globe. These stations will have ranges of 
thousands of miles and their object will be conoimercial 
service. 

Already there are other fields of usefulness for wireless 
as in the city police service, the government forestry serv- 
ice, the weather bureau, accurate time signalling, in isolated 
mining regions, the fisheries and in the collection and 
transmission of news. What the future holds no man dare 
prophecy for the dreams of yesterday are eclipsed by the 
achievements of today. Certainly the sphere of usefulness 
for radio transmission will ever widen and the dream of 
transmitting energy in vast quantities by means of elec- 
tromagnetic waves may, indeed, come true. This is surely 
the age of dreamers and they have a wonderful faculty 
for bringing the "impossible" to pass. 

But we must not forget to pay tribute to the very im- 
portant part which the American boy has played in the 
development of wireless service. Wireless appealed to the 
imagination and practical instincts of boys everywhere 
and wireless amateur stations sprung up in every town and 
hamlet from Maine to California.- Boys built their own 
apparatus and constructed their stations. These stations 




By courtesy of Electrical Experimenter. 

Amateur wireless laboratories. 



The Triumph of Wireless 91 

have performed very useful work on numerous occasions. 
In 1 9 13, when the Middle Western States were swept by 
flood and all telegraph and telephone lines were cut 
these amateur wireless stations preserved communica- 
tion with the outside world and assisted in the rescue work. 
The American Radio Relay League comprising 4000 mem- 
bers, 1000 of whom were experts, estabHshed transcon- 
tinental service starting at Valley Stream, Long Island, 
and following a path which included Lima, Ohio, Chicago, 
Dallas, Texas, San Diego and Los Angeles. These am- 
ateurs have given much assistance to naval and commer- 
cial operators in receiving long distance messages. 

Although these stations have been dismantled for the 
period of the war, the amateur operators have proved a 
great asset to the nation and in large numbers have been 
recruited into the national service. England, unlike the 
United States, was without amateurs at the beginning of 
the war and was compelled to train a large body of wire- 
less men. Although now suffering an eclipse, the day of 
the amateur is bound to return and the American boy 
can once more satisfy his love for the wireless art. 



Chapter VI 
THE THEORY AND PRACTICE OF WIRELESS 

As has already been shown the success of wireless teleg- 
raphy depends upon the setting up of electromagnetic 
waves in the ether of space. Before we go further it may 
be well to inquire what we mean when we speak of the 
ether. It is known that outside of the earth's atmosphere, 
which extends at most but a few hundred miles above the 
surface, there exists a vacuimi inconceivably better than 
any ever produced by mechanical means. And yet Hght 
and radiant heat energy travel ninety-three millions of 
miles from the sun to the earth supplying all the energy 
for the planet upon which we Hve. Now it is unthinkable 
that light and heat should travel this distance, or any dis- 
tance for that matter, without some transmitting mediimi 
and therefore we assume that such a medium, which we 
call the ether, exists. An incandescent lamp bulb contains 
a vacuum and yet light and heat travel from the glowing 
filament through it and affect our senses of sight and touch. 
We must assume that the vacuum is filled with something 
that transmits this energy and this something we call ether. 
Likewise between us and the distant stars must stretch 
for infinite distances this intangible, weightless,- yet all 
pervading fluid. 

It must be assumed that the reader of this book has an 
elementary knowledge of electricity and magnetism and 
if not he is referred to any standard text for this in- 
formation. 

92 



The Theory and Practice of Wireless 93 

Wireless telegraphy may be divided into four operations: 

1. The setting up of electrical oscillations. 

2. The transfonnation of these electrical oscillations 
into electromagnetic waves. 

3. The transformation of the electromagnetic waves 
back into electrical oscillations. 

4. The detection of these oscillations. 

The first two sets of operations are performed by the 
transmitter and the second two by the receiving mechan- 
ism of a wireless outfit. 

As previously indicated electrical oscillations are set 
up by the Kghtning-like discharge between the secondary 
terminals of an induction coil or by the discharge of a 
condenser and also by the discharge from the secondary 
of a transformer. These oscillations at the same time 
impart electromagnetic vibrations to the surroimding 
ether which traveling with the velocity of light are caught 
by some distant recei\'ing aerial and there set up in the 
receiving circuits oscillations which can be detected in a 
telephone receiver. This setting up of electromagnetic 
vibrations in the great ocean of ether is very similar to 
the production of water waves by the tossing of a pebble 
into a pond. In each case waves are produced which travel- 
ing outward in ever widening circles dissipate their energy 
as they go and finally disappear. A floating chip catching 
a small portion of the energy in the water waves rises and 
falls thus serving as a detector and performing the same 
fimction as the aerial and receiving circuits for electro- 
magnetic waves. 

The Induction Coil. — Although the induction coil is no 
longer used for wireless transmission, wherever alternating 
current is available, its use in the past has been so impor- 
tant and it is still used so frequently in the absence of 



94 



The Boys' Own Book of Great Inventions 



alternating current that a brief explanation of its con- 
struction and operation is desirable. 

The construction of an induction coil is shown in the 
accompanying diagram. Its essential parts are a core 
made up of soft iron wires, a primary coil, a secondary 




Fig. 26. — An induction coil. 

coil, an interrupter and a condenser. The primary coil 
consists of a comparatively few turns of rather coarse 
insulated copper wire wound upon the soft iron core. The 
secondary overlies the primary, being wound upon a hollow 
spool and consisting of very many turns of fine insulated 
wire the ends of which terminate in large brass knobs with 
a spark gap between. The interrupter shown here is of 
the magnetic vibrator type with a platinum contact point 



The Theory and Practice of Wireless 95 

resting against a similar point on the contact screw. The 
condenser is made up of two sets of tin-foil plates insulated 
from each other, one set being connected to one side of 
the make and break gap of the primary circuit and the 
other set to the opposite side. 

The action of the induction coil is as follows: The primary 
is connected with a set of batteries and as the current flows 
through the circuit the soft iron core becomes an electro- 
magnet drawing over the soft iron vibrator and thus break- 
ing the circuit at the platinum contact points. This break- 
ing of the circuit demagnetizes the soft iron core and the 
vibrator springs back making the circuit and repeating the 
operation. Thus the making and breaking of the primary 
circuit occurs at a rapid rate, causiug the lines of magnetic 
force surrounding the primary coil alternately to cut out 
across the turns of the secondary and then to surge inward 
cutting back across them in the opposite direction. Now 
whenever lines of force are made to, cut across a conductor 
an electromotive force or difference of electrical potential 
is induced in that conductor. The intensity of this electro- 
motive force is proportional to the rate of cutting of the 
lines of force, and therefore will depend upon the number 
of lines of force, the relative number of turns of wire on 
the secondary and the rate at which the field is built up 
or dies down. When the difference of potential between 
these terminals becomes sufficiently high a discharge will 
occur across the spark gap and a set of electrical oscilla- 
tions will be set up. 

Another factor which will explain the use of the condenser 
must be taken into account. It will be seen that as the 
primary field builds up, the lines of force surge outward 
not only across the secondary but across the primary as 
well. And therefore from the law of induced currents a 



96 The Boys^ Own Book of Great Inventions 

self induced current will be set up in the primary itself 
which will oppose the battery current and prevent a rapid 
building up and surging outward of the lines of force. Since 
the electromotive force of the secondary depends upon 
the rate of cutting of the lines of force, it will be seen that 
the self induction on the make tends to prevent a rapid 
cutting and results in a low electromotive force, so low 
that it is insufficient to puncture the air gap and produce 
a spark. As the lines surge inward, too, on the break a 
current is self induced in the primary but this time tending 
to prolong the battery current and to prevent a rapid 
dying down of the field. This self induced current mani- 
fests itself as a spark at the contact points and as long as 
this spark passes the primary current continues to flow. 
Now in order to overcome this effect of self induction on 
the break a condenser is placed across the contact points 
and the high E. M. F. of the self induced current, first 
charges the plates of the condenser instead of producing 
the spark and then, discharging back through the primary 
in the opposite direction to which the battery current is 
flowing, destroys this current instantaneously and pro- 
duces a very rapid cutting of the lines of force. Therefore 
a discharge of the secondary occurs only on the break. 
This discharge as wiU be shown later is oscillatory and 
gives rise to electromagnetic waves. 

The Condenser. — ^The construction of the Leyden jar 
form of condenser will become apparent from the accom- 
panying figure. It is easily made and much used in wire- 
less work. Such a condenser may be charged in the simplest 
manner by placing the brass knob in connection with one 
terminal of an induction coil or static machine, say the 
negative, and taking hold of the outside tinfoil with the 
hand. As the induction coil or static machine is operated, 



The Theory and Practice of Wireless 



97 



negatively charged particles called electrons pass onto 
the knob and streaming through the brass rod spread over 
the inner tinfoil, at the same time repelling an equal num- 
ber of electrons from the outer tinfoil through the body 
of the operator to the ground. 
Thus the inner surface of the glass 
jar in contact with the tinfoil comes 
to be charged negatively and the 
outer surface positively, for the neg- 
ative electrons repelled to the earth 
leave an excess of positive electricity 
on the outside of the jar. 

If now the outer coating of tin- 
foil be brought close to the knob 
of the jar by means of a bent brass 
rod with an insulating handle, a 
powerful spark will pass. Although 
this discharge seems to be a single 
instantaneous spark it is really made 
of a large number of rapid oscilla- 
tions, or to and fro surgings. The first passage of current 
serves to more than discharge the condenser coatings and, 
overshooting its mark, as it were, charges them in the oppo- 
site direction. A reverse discharge then occurs which again 
overshoots itself and the process is repeated over and 
over giving rise to a series of oscillations which growing 
weaker and weaker gradually die down or are ^'damped'' 
out as is said. It is these electrical oscillations which 
give rise to the electromagnetic waves of wireless teleg- 
raphy. 

A consideration of the action of a spiral spring to which 
is attached a weight may help to make more clear the 
matter of electrical oscillations and also to show the rela- 




FiG. 27, — A Leyden jar. 



98 The Boys^ Own Book of Great Inventions 

tion and meaning of two very important factors in all 
oscillatory circuits, namely inductance and capacity. 

If we suspend the spring and weight as shown and charge 
the system, so to speak, by pulling the weight down 

and then discharge it by 
letting go, we shall get a 
series of reactions very sim- 
ilar to those occurring dur- 
ing the charging and dis- 
charging of a Leyden jar. 
The weight does not simply 
return to its starting point 
and stop but its inertia 
carries it by this point and 
it oscillates up and down, 
the oscillations gradually 
dying down until the weight 
is again in its original posi- 
tion. Now there are two 
forces that are governing 
this oscillatory motion, the 
springiness or elasticity of 
the spring and the inertia 
of the system. By inertia 
we mean the opposition of- 
fered by the weight either 
to starting the motion from 
^^^' ^^- rest or to stopping the mo- 

tion when the weight in its upward movement reaches the 
middle point. 

Now what is the effect of each of these factors on the 
resistance of the system and the nimiber of oscillations? 
If we gradually increase the weight we increase the resist- 




The Theory and Practice of Wireless 99 

ance to the motion, and the amplitude, or distance moved 
through, becomes less and the number of oscillations fewer. 
That is, an increase of the inertia "damps" out the oscilla- 
tions and it can readily be seen that if we make the weight 
great enough there will be no oscillations at all. When 
the weight is drawn down it will simply come back to its 
position of rest and stop. To increase the elasticity of 
the spring, however, increases the amplitude of the move- 
ment, lessens the resistance and increases the nimiber of 
oscillations. Thus it will be 
seen that the elasticity ef- 
fect tends to neutralize the 
inertia effect so far as the 
number and amplitude of 
the oscillations is concerned. ' ^* 

If we could attach a pencil at right angles to the moving 
weight and allow it to trace a record of the oscillations on a 
moving sheet of paper the result would be as shown in 
Fig. 29. This gradual decrease of the wave movement 
is called damping. 

There are other factors which affect the resistance to 
the oscillatory motion. In the case of the spring and 
weight some energy is imparted to the air and if we should 
make the system vibrate in water or thick syrup the amount 
of energy imparted to the surroimding medium would be 
still greater. We might also cause this spring system to 
impart energy to another spring system, setting it into 
vibration. All of these factors would have the effect of 
additional resistance and decrease the amplitude and 
number of oscillations. 

Now let us make a comparison between our mechanical 
spring system and the oscillatory discharge circuit of a 
Leyden jar. At the start let us fix clearly in mind that 



lOO The Boys^ Own Book of Great Inventions 

the capacity effect of an electrical circuit corresponds to 
the elasticity of the, spring and the inductance effect to 
the inertia of the system. A consideration of the self 
induction in the primary circuit of an induction coil, will 
make clear the meaning of inductance. Inductance op- 
poses either the setting up or dying down of an electrical 
current. To give another mechanical analogy for capacity, 
we may say that it is the same as the number of cubic 
feet of air that must be forced into a tank to raise its pres- 
sure one pound per square inch. Capacity tends to in- 
crease the flow of electricity, inductance chokes it back. 
The potential energy stored up in the elasticity of the air 
in the air dome of a force pump would be capacity, while 
the friction of the pipes and the inertia of the water would 
be inductance. 

As already explained the discharge of a Leyden jar is 
oscillatory. Just as the weight and spring do not stop at 
the middle point of the upward swing but move by it, 
charging the system in the opposite direction and con- 
tinuing to charge and discharge it alternately until the 
resistance dam.ps out the oscillations, so the discharge 
of a Leyden jar does not stop at the middle point, so to 
speak, but charges the condenser surfaces in the opposite 
direction and the process continues until the oscillations 
are damped out as before. At the same time the spark 
discharge imparts energy to the surrounding ether in the 
form of electromagnetic waves and this corresponds to 
the energy imparted to the air or other medium sur- 
rounding our spring system. This is the real fimction of 
a wireless transmitting set as we shall see. The greater 
the capacity, the greater the number of oscillations. But 
any resistance such as that of the air in the spark gap will 
decrease the number of oscillations. The amoimt of in- 



The Theory and Practice of Wireless 



lOI 



ductance in a simple Leyden jar is very small but the exact 
relation of capacity and inductance in a wireless oscillatory 
discharge circuit will be fully explained a Httle later. 

The capacity of a condenser will depend upon its size. 
There are other forms of condensers than the Leyden jar, 
the construction of which will follow later. Condensers 



Fig. 30. 



Fig. 31. 



may be grouped in parallel as shown in Fig. 30 or in series 
as shown in Fig. 31. In the parallel grouping the total 
capacity is the sum of the separate capacities of the con- 
densers, while if in series it is equal to the sum of the re- 
ciprocals of the separate capacities. Therefore to increase 
the capacity of a circuit place condensers in parallel and 
to decrease it place them in series. 

Any circuit possesses capacity and inductance and their 
importance will become apparent when we consider the 
frequency of oscillations and the tuning of circuits into 
resonance with each other. 

The Transformer. — For the purpose of charging con- 
densers and producing the electrical oscillations for wire- 
less work the transformer is now used in all commercial 
work and for amateur work wherever possible. It is in 
principle identical with the induction coil but for the direct 
current and interrupter of the primary circuit an alternat- 
ing current of from 60 to 500 cycles per second is substituted. 
Every dynamo current as generated in the armature is 



I02 The Boys^ Own Book of Great Inventions 

alternating and may be taken off in the external circuit 
either as alternating or direct. By a cycle is meant the 
building up of the E. M. F. from zero to a maximum, its 
dying down to zero, its building up to a maximum in the 
opposite direction and its dying back to zero again. This 
cycle of changes takes place during one revolution of the 
single loop armature of a two-pole dynamo. It will be 
seen then that in each cycle there are two reversals of 
current and therefore a 60 cycle current reverses itself 
at the rate of 1 20 times per second and a 500 cycle current 
makes 1000 reversals per second. 

A transformer consists essentially of a soft iron ring 
with two windings, a primary and a secondary. Trans- 




• •- 



Fig. 32. — A transformer. 



formers are of two general types, step up and step down. 
One raises the voltage and decreases the current while 
the other produces the opposite effect. It is the step up 
transformer that is used for wireless transmission and the 
principle of its construction is shown in the diagram. Just 
as in the induction coil when the current in the primary 
winding passes in one direction the lines of force surge 
outward, cutting across the secondary winding and as the 
current reverses itself the lines of force cut the secondary 
in the opposite direction. Also as in the induction coil 



The Theory and Practice of Wireless 



103 



this induces a high E. M. F. in the secondary producing 
a discharge across the spark gap and generating a train of 
electrical oscillations. 

Aerials — The simple oscillator of Hertz or the discharge 
from a Leyden jar is unable to use for the production of 
electromagnetic waves very much of the energy in the 
spark discharge. Consequently the waves emitted are 
very feeble and very short. They carry but a short dis- 
tance and are much interfered with by obstructions such 
as buildings, forests and hills. Marconi early found that 
he could greatly increase the distance of transmission by 
attaching to one terminal of the spark gap of his induction 
coil a ground wire and to the other terminal a wire leading 
high into the air and having a metallic plate fastened to its 
upper end. This not only lengthened the wave but increased 
very much the capacity 
of his transmitter. The 
aerial and the earth then 
become a huge condenser, 
one being charged posi- 
tively and the other nega- 
tively. This increased ca- 
pacity increased the quan- 
tity of the electrostatic 
charge that could be stored 
up for the production of 
the oscillatory spark and 
also increased many times 
the amount of energy available for the generation of elec- 
tromagnetic waves. 

The conditions just previously to the discharge are 
shown in Fig. 33. Lines of electric strain are set up in the 
ether and pass from the antenna, as the aerial is called, 



+ 



V N \ \ 



' _L_L 



O I I 



• I I !■ 
I I , I I , I 
I I I ' • i I 

• • • I • ' ,T 



Fig. 33. 



I04 



The Boys^ Own Book of Great Inventions 



to the earth repelHng each other outward into a pear shape. 
When the difference of potential becomes great enough, 
the insulation of the spark gap breaks down, the spark dis- 
charge occurs and the upper ends of the lines of electric 
strain rush down to meet the lower ends as shown in Fig. 34. 
This produces a train of electromagnetic waves which ra- 



X\r>N\>'\\ 



o \ 
o '. 



\ \ 
\ \ 
1 \ 



Fig. 34. 

diate outward with the velocity of light and are the waves 
which make wireless telegraphy possible. Just as in the 
case of the Leyden jar this discharge is oscillatory and a 
series of wave trains are sent off. The greater part of the 
total energy of the discharge is used in the spark gap, a 
portion heats the antenna and the remainder generates 
the electromagnetic waves. 

These waves in the form of a series of half loops with 
their feet on the ground move outward over the earth 
and sea. The sea is a better conductor than land and 
moist earth better than dry earth. Therefore transmission 
is better over sea than over land and better over a region 
of plentiful rainfall than over a desert. 

The length of the wave radiated off is approximately 
four times the length of the aerial and the effective length 



The Theory and Practice of Wireless 105 

of this aerial may be increased by introducing at the bottom 
of it a spiral coil of wire called an inductance coil. And 
here we meet inductance again. Inductance therefore 
decreases the frequency or rate of oscillation and increases 
the wave length. An increase of capacity will also de- 
crease the rate of oscillation and lengthen the wave. There- 
fore it will be seen that the wave length, so important in 
tuning wireless circuits into resonance, depends upon the 
two factors of capacity and inductance. Wireless waves 
vary in length from 200 meters and less, used in amateur 
work, to 1600 meters and sometimes more for commercial 
work. The two standard wave lengths for commercial 
work are 300 and 600 meters. A meter is a Httle more than 
3 feet, or 39.37 inches. 

Marconi soon found that he could increase the capacity 
of his aerial much more effectively by using several parallel 
antennae joined above and below than by using a metal 
plate. Several of the more common forms are shown in 
Fig. 35. The chief purpose of any aerial is to increase the 
amount of energy that can be stored and radiated. 

Electrical Resonance. — There is no more important factor 
in practical wireless work than the matter of resonance 
and tuning. In the transmitting set the oscillation trans- 
former must be tuned into resonance with the aerial cir- 
cuit and in the receiving set the aerial circuit must be 
tuned to resonance with the closed oscillation circuit in 
which is placed the detector and telephone receiver. 

An illustration from the properties of musical instru- 
ments will make clear what wx mean by resonance. It 
will be recalled that Bell caught the idea of a musical 
telegraph from the fact that when he sang a particular 
note close to the keys of a piano, the string of the same 
pitch would answer him. In like manner if we set a tuning 




Fig. 35. — Several t)T)es of antennae. 



The Theory and Practice of Wireless 107 

fork into vibration and place near to it another fork of 
the same pitch, or rate of vibration, the second fork will 
be set to vibrating. This can be detected by touching the 
first fork so as to stop its vibration when the second fork 
will be found to be emitting a clearly audible note. A 
tuning fork sends forth a definite nimiber of waves per 
second, each wave having a definite length. In like manner 
an electrical oscillation circuit sends out a definite number 
of waves per second, each wave having a definite length. 
Electrical oscillation circuits also have a definite pitch 
and can be tuned into sympathy with each other just the 
same as two tuning forks can. 

As we have seen in the case of an aerial the rate of vibra- 
tion of an oscillation circuit depends upon two factors, 
capacity and inductance. An increase of either decreases 
the number of oscillations in a second and increases the 
wave length. Now if as with our tuning forks one oscil- 
lation circuit is to be set into sympathetic vibration with 
another the values of the capacity and inductance in 
each circuit must be such as to make the natural vibration 
rates of the two circuits the same. These values do not 
have to be the same in each circuit but their products 
must be the same. Just as we can have two sets of factors 
each of which will produce 12, so we may have two sets of 
capacity and inductance each of which will give the same 
oscillation frequency to its circuit. 

Let us consider the two oscillation circuits shown in 
Fig. 36. This is the conventional way of representing the 
** coupling'^ of two such circuits. The circuit at the left 
is the primary and that at the right the secondary. The 
condenser is at C, the inductance coil at L and the spark 
gap at S. A hot wire ammeter is placed in the secondary 
circuit at A so as to detennine when the maximum effect 



io8 



The Boys^ Own Book of Great Inventions 



is produced and the two circuits are most closely in tune. 
The capacity in each circuit is a fixed quantity but the 
amount of inductance may be varied by the movable con- 
tacts. Across the spark gap of the primary circuit is con- 
nected an induction coil or transformer. As the primary 




Fig. 36. 

circuit becomes charged and the spark discharge occurs 
at S the electromagnetic waves sent off will induce oscilla- 
tions in the secondary circuit giving a deflection of the 
ammeter needle. By moving the adjustable contact along 
the coil in the secondary circuit and thereby varying the 
inductance a point can be found where the deflection of 
the ammeter needle is greatest. This means that the two 
circuits are timed into resonance with each other. This 
condition is reached when the product of the capacity and 
inductance in one case is equal to their product in the other. 
But if these products differ very much there will be little 
or no oscillation in the secondary circuit. 

Coupling of Circuits. — There are two general methods 
by which the antenna circuit may be set into oscillation. 
Either the spark gap of the transformer or induction coil 
may be placed directly in the antenna circuit as shown in 
Fig. 37, or the spark gap may form a part of a closed oscilla- 



The Theory and Practice of Wireless 



log 



tion circuit inductively coupled to the antenna circuit as 
shown in Fig. 38. The former was the early method em- 
ployed but the latter is now used almost altogether. 

In the direct excitation of the antenna circuit the wave 
length to be radiated was regulated by a variable induct- 






FiG. 37. 



Fig. 38. 



ance at L. A condenser is sometimes placed between the 
spark gap and the ground. Being in series with the oscillat- 
ing circuit the condenser has the effect of diminishing the 
total capacity of the circuit and therefore increases the 
rate of oscillation and shortens the wave length. 

In the method employing inductive coupHng the closed 
oscillation and antenna circuits must be tuned into close 
resonance with each other. But another factor comes in 
here which is of considerable importance. These two 
circuits may be ''closely" coupled or ''loosely" coupled. 
The two coils here, the one in the closed circuit and the 



no The Boys^ Own Book of Great Inventions 

one in the open antenna circuit, constitute the oscilla- 
tion transformer. Now if the coil in the closed circuit 
is brought close to the coil in the open circuit or, per- 
haps, telescoping inside of it the coils are said to be closely 
coupled. But if these coils are drawn apart the coupling 
is loose. With the loose coupling not so much energy is 
transferred into the aerial circuit but on the other hand 
with the close coupling the oscillations of the antenna cir- 
cuit will retransfer energy back into the primary circuit. 
This latter condition results not only in a loss of energy 
but, what is a greater disadvantage, it gives rise to the 
radiation of two waves from the aerial instead of one. A 
receiving station can be timed to resonance with only one 
of these waves, the energy in the other wave being lost 
and besides needless interference with other radio stations 
is caused. A wave meter will show when the coupHng is 
right. Close coupling usually results in what is called a 
*' broad wave," while the loose coupling gives a *' sharp wave." 
The broad wave is quickly damped out while the sharp 
wave does not damp out so quickly and requires ^^ sharp 
tuning," that is, the receiving circuits must be closely ad- 
justed to place them in resonance. 

In this connection it may be said that what is called a 
quenched spark gap prevents the retransfer of energy from 
the aerial circuit back to the condenser circuit even with 
close coupling. This results in the radiation of a single 
wave. Such a spark gap consists of a mmiber of heavy 
copper plates separated by thin mica washers placed in 
an iron rack and compressed by a pressure bolt. The 
spark gap between two adjacent plates is not over .01 
inch. 

The essential parts of a modem wireless transmitting 
set are shown in Fig. 39. They are: 



The Theory and Practice of Wireless 



III 



1. Source of alternating current or storage batteries S. 

2. Step up transformer or induction coil T. 

3. A telegraph key K. 

4. A battery of condensers C. 

5. A spark gap G. (Quenched preferable.) 




jf^ 



Fig. 39. — ^A wireless transmitting set. 



6. Oscillation transformer 0. T. 

7. Hot wire ammeter A. for tuning transmitter. 

8. Aerial timing inductance I. (Not always used.) 

9. A short wave condenser S. C. to shift from one wave 
length to another. 

Receiving Apparatus. — ^The function of the receiving 
aerial is to absorb a portion of the energy from an advancing 
electromagnetic wave and transfer it to a receiving circuit. 
What the electromagnetic waves actually do is to induce 



112 The Boys^ Own Book of Great Inventions 

electrical oscillations in the receiving aerial which can be 
made to operate some sort of detecting device. 

As we have seen Marconi used the coherer for this purpose 
but this has long since been superseded by more sensitive 
detectors. The telephone receiver is one of the most sensi- 
tive instruments for the detection of feeble currents and 
has come into universal use. It works best with an alter- 
nating current of from 300 to 500 cycles per second and 
therefore the unaided receiver cannot detect the very rapid 
oscillations of wireless currents. Very fortunately, how- 
ever, it has been found that certain minerals such as iron 
pyrites, zincite, bornite, galena, silicon and carborundum 
have the property of allowing an electric current to flow 
through them in one direction but not in the opposite. 
Therefore if such a ^^ rectifier'^ is placed in a 
circuit in which an oscillating electric current 
is flowing, this current will be converted 
into a direct or pulsating current. 

The simplest arrangement for a receiving 
set is shown Fig. 40. The detector is at D, 
the head telephone at T. The first require- 
ment is to tune the open circuit of the re- 
ceiving aerial into resonance with the open 
circuit of the distant transmitting aerial. 
This is done by varying the inductance in 
L, and frequently an adjustable condenser 
'^ is also placed between the detector and the 

Fig. 40. ground. 

The action of the apparatus is as follows: A train of 
waves radiated from the transmitting aerial induces an 
alternating current of high frequency in the aerial receiving 
circuit. This current flows freely through the crystal 
detector in one direction, but is blocked in the opposite 




The Theory and Practice of Wireless 



113 



direction. Suppose this current passes from the earth 
up through the detector placing a charge on the antenna. 
The return current being opposed this charge accumulates 
imtil the passage of the wave train, when it discharges to 
the earth through the head telephone, producing a musical 
note. There will be one note for each wave train, and it 
may be short or long representing a dot or a dash. 

It is better, however, to place the detector in a local 
detector circuit and not in the antenna circuit because 
the detector hinders the free 
flow of oscillations and destroys 
somewhat the tuning qualities 
of the aerial circuit. The ar- 
rangement is shown in Fig. 41. 
The aerial circuit must now be 
tuned into resonance with the 
transmitting aerial and the de- 
tector circuit as well. A vari- 
able condenser is placed at C 
for tuning purposes. As before, 
the oscillations set up in the detector circuit flow through 
the detector in one direction charging the fixed condenser 
at C and at the end of each wave train discharge through 
the telephone producing a sound. 

Another device employed in the receiving set is the 
potentiometer. It has been found that the application 
of a weak battery current to the crystal detector and head 
telephone increases to a very marked degree the intensity 
of the incoming signals. The potentiometer consists of a 
resistance connected with a battery as shown in Fig. 42. 
By sHding the movable contact K along the variable re- 
sistance a position can be found where the signals are most 
distinct. 




Fig. 41. 



114 



The Boys' Own Book of Great Inventions 



Sending and Receiving. — When an operator wishes to 
send a message he first ^'listens in" to determine whether 
messages are passing which have the same wave length 
as he wishes to use. Finding that there are none he switches 



VARlABtt RCSl6tANCt 




Fig. 42. 

his transmitting apparatus to the aerial, and adjusts it to 
the proper wave length. The same aerial serves for both 
sending and receiving and at the same time that the sending 
set is switched in the receiving set is disconnected. He 
now presses the key and sends out the call letters of the 
station with which he wishes to get into communication, 
repeating the signals several times. He then switches 
out the transmitter and throws in the receiving set. If 
his call is answered he can begin to send at once. 

Amateurs find it far more interesting to receive than to 
send, and a boy frequently starts with a receiving set only. 
The simplest sort of receiving set would consist of an aerial, 
a tuning-coil, fixed condenser, detector and receivers. 
With such a set installed the operator places the receivers 
on his ears and turns the adjustable thumb-screw on the 
detector until a distinct snapping soimd is heard. A con- 
fusion of sounds will usually be heard from stations within 



The Theory and Practice of Wireless 115 

range of his instruments. In order to eliminate all but a 
single message and hear that distinctly, he moves the 
sliders along the tuning coil until clear musical notes tell 
him that he is in tune with some distant station and he is 
able to catch the message. 

TWO WIRELESS EXPERIMENTS 

1. The experiment of Sir Oliver Lodge, previously de- 
scribed, may easily be repeated by any boy. For a static 
machine substitute an induction coil, and in order to bring 
the inner tinfoil coating of the second Leyden jar close to 
the outer coating let a strip of tinfoil be brought over the 
edge of this jar from the inner coat to about one-sixteenth 
of an inch from the outer coat. For the loops coarse copper 
wire may be used. The loop of the jar connected to the 
induction coil will be closed and of fixed length. The 
other loop will be closed through a sliding contact so that 
the second Leyden jar may be tuned into resonance with 
the first. In the primary circuit of the induction coil in- 
sert a key or simply make and break the circuit by tapping 
the wires together. When the sliding contact has been 
adjusted so that the values of capacity and inductance in 
each circuit are the same, at each discharge of the first 
Leyden jar a small discharge will appear at the spark gap 
of the second. The Leyden jars should be of the same 
size and the two circuits parallel with each other. 

In this simple experiment electrical oscillations are set 
up which produce electromagnetic waves, and in turn 
induce electrical oscillations in the second jar. The prin- 
ciple of tuning is also involved. 

2. In a small glass tube about a quarter of an inch in 
diameter and three inches long place some fine brass or 



ii6 The Boys' Own Book of Great Inventions 

nickel filings held in place by pieces of cork having a notch 
cut in the side of each. Through these notches thrust 
copper wires into the filings and connect them through 
two dry cells with an electric bell. If the bell begins to 
ring tap the tube containing the filings, jarring them apart 
so that the resistance will be so great that not enough 
current will flow to ring the bell. Then off at a Httle dis- 
tance set an induction coil or transformer into operation 
and at the discharge and passage of the spark the bell will 








Fig. 43. — A simple coherer. 

begin to ring. Tap the tube, and repeat the operation. 
At each spark the bell will ring. 

We have here a simple coherer. When the electromag- 
netic waves from the oscillatory spark discharge fall upon 
the loose filings in the tube they cohere so as to form a 
path of low resistance, and permit the flow of current and 
the ringing of the bell. The tapping of the tube to jar 
the filings into a state of high resistance performs the func- 
tion of a decoherer. 

Fig. 43 shows the arrangement of the apparatus. 

A Simple Wireless Set. — ^A simple sending and receiving 
set may be made and put into operation as follows: 

The Sending Set 

The Aerial. — The flat top aerial is one of the easiest to 
erect and excellent for amateur work. Its height should 




By courtesy of Clapp-Eastham Company. 

Helix, detector, timing coil, complete receiving set and transformer, mounted and 

unmounted. 



The Theory and Practice of Wireless 117 

be from 40 to 60 feet and the ends may be attached to poles 
fastened to the tops of trees or to the roofs of buildings. 
If attached to trees, they should extend above the leaves 
and branches. The length of the aerial should be about 
twice its height or a Uttle less. Very frequently poles 
may be fastened to the roofs of two adjacent buildings 
and the wires stretched between. 

Secure two strong wooden bars about two inches in 
diameter and seven feet long. At six inches from each 
end and in the middle of each fasten porcelain insulators. 
Lay the bars on the ground at a distance apart equal to 
the desired length of the aerial. Cut three lengths of No. 12 
copper or aluminum wire and fasten the ends to the insu- 
lators. To the middle of each wire solder a long copper 
wire. These three wires make what is called the ''lead-in" 
and should be joined together just before entering the 
building. Fasten three short ropes to each bar and tie 
their ends together. From these ropes lead another over a 
pulley on the top of the pole and make secure to the build- 
ing or tree. Each pole should be strengthened with guy 
ropes. 

The lead-in wire should be connected to a single pole 
double throw sw^itch just before entering the building as 
shown in Fig. 44 as a Hghtning protector. When the 
set is not in use the aerial is connected with the ground, 
and thus there is no danger of a Hghtning discharge into 
the building and apparatus. 

Next on the wall just inside the building where the ap- 
paratus is to be set up place a two pole double throw switch 
as shown in Fig. 45, so that the same aerial may be used 
for both sending and receiving. 

A good ground is important and in the country this can 
frequently be obtained by immersing metal plates in a 



ii8 



The Boys^ Own Book of Great Inventions 



cistern or well. In the village or city a heavy copper wire 
may be attached to a gas or water pipe. This ground wire 
is independent of the one for the lightning arrester and 



< 
o 



Y 



Fig. 44. 

by means of the double throw switch may be connected 
either with the sending or receiving apparatus. 

The Spark Coil. — For the production of the spark either 
batteries and an induction coil may be used or, if alter- 
nating current is available, a small wireless transformer 



The Theory and Practice of Wireless 



119 



will be simpler to install and operate. If the set is to be 
used in the country, an induction coil must be employed, 
and a small one or two-inch coil may be purchased for a 
few dollars. It will be better to buy this than to attempt 



V 




Fig. 45. 

to make it. In purchasing a transformer it will be neces- 
sary to specify the voltage and mmiber of cycles of the 
current to be used. This will usually be no volts and 60 
cycles. Storage batteries or dry cells may be used with 
an induction coil. 

Spark Gap. — ^A spark gap may be made by screwing 
two brass binding posts into a board 4 inches square to 
hold the spark terminals. Then cut two pieces from a % 
inch zinc battery rod about % inch long. Bore and thread 



I20 



The Boys^ Own Book of Great Inventions 



these and fit into them a pair of brass rods Vs inch in diam- 
eter by 3 inches long. Place a piece of hard rubber on 

each rod for a handle and 
moimt them in the binding 
posts as shown in the figure. 
Key. — ^An inexpensive key 
to place in the primary circuit 
of the induction coil or trans- 

FiG.46.-Sparkgap. f^^^^j. ^^^ j^^^^ be bought. 

Condenser. — ^The condenser for the oscillation circuit 
can be made as follows: Get 24 thin glass plates 5 by 7 
inches or about that. Photographic plates from which the 
gelatin has been removed will be excellent. Next cut 24 
sheets of tinfoil 3 by 5 inches leaving a small projection, or 





Fig. 47. — Oscillation heHx. 
"lug," on one corner of each. Place these alternately be- 
tween the plates of glass so that half of the lugs project on 
one side and half on the other. Connect the tinfoil lugs 
on each side to a thin strip of copper foil. Then place the 
condenser in a wooden box of suitable size and pour full of 
paraffin leaving the copper strips exposed for connecting 
in the circuit. Fasten them to binding posts if possible. 



The Theory and Practice of Wireless 



121 



Oscillation Helix. — Build a circular frame of wood about 
lo inches high and 9 inches in diameter. Cut grooves in 
the uprights about ^/g of an inch apart and wind in them 
3^ inch brass wire. Secure the wire by means of small 
claw tacks. Insert two binding posts in the wooden top 
and fasten one to the lower terminal of the wire. Short 
flexible leads with spring clips should be attached to the 
two upper posts as shown in Fig. 47. 



The Receiving Set 
The Detector. — To a base board about 3 by 4 inches 



fasten an L shaped piece of brass ^ inch wide and Vs inch 




Fig. 48.— Detector. 

thick by means of a screw binding post. Make this strip 
about 4 inches high and directly in under the horizontal 



122 



The Boys' Own Book of Great Inventions 



part place a small square of sheet brass. To this horizontal 
portion attach a fine brass wire and allow it to rest on a 
small piece of crystal carborundvun or galena. Insert 
another binding post in the sheet brass and the detector 
will be ready for testing and adjustment. 

The Condenser. — ^This may be made as before but this 
time use 13 sheets of waxed paper instead of glass 3 by 
5 inches and 12 sheets of tinfoil 2 by 4 inches. Provide 
connections as in the glass plate condenser. 

The Tuning Coil. — Procure a hard- wood board 12 inches 





?i 




""■■ ■ ^. 




p - 


T 


-A 


t - 


i 


- 1 






- —V 


r- 




^"^ 



Fig. 49. — Timing coil. 

long, I inch thick and 6 inches wide. At each end place 
a wooden head 4 inches square and between these moimt 
a wooden cylinder 9 inches long and 3 inches in diameter 
leaving space beneath for puUing the wire. On this cylin- 
der wind as closely as possible without actual contact 
No. 22 cotton-insulated copper wire and secure one end to 
a binding post screwed into the wooden head of the coil. 
This terminal will be connected both to the ground and 
to the receiving circuit. Across the top and one side of the 
wooden ends place brass rods carrying brass sliders and 
terminating in binding posts. The sliders may be made 
from sheet brass or copper bent to shape and should carry 
a set-screw and thumb-nut for fastening in position. With 



The Theory and Practice of Wireless 



123 



a red-hot iron burn off the insulation in straight lines 
directly underneath the rods and sliders. 

The Receivers. — These must be bought and should be of 
1000 ohms resistance. 

Both the transmitting and receiving sets may now be 
assembled on a bench or table in the attic or wherever the 



W 



{V—^ 






W 



Q? 



Fig. 50. — Installation of receiving and sending set. 

"wireless laboratory'' is to be and connected up for opera- 
tion. A diagram illustrating the proper connection is 
shown in Fig. 50. The lightning arrester previously de- 
scribed is not shown here. In both the oscillation helix 
of the transmitting set and the tuning coil of the receiving 
set close coupling is employed. Such a station will give 
to a boy the fijst essentials of amateur training and he 
may enlarge upon his equipment as his knowledge ^jid 
experience grow. 



Chapter VII 
TALKING THROUGH THE ETHER 

From the time that wireless telegraphy became a fact 
it was theoretically possible to talk through the ether as 
well as to send the dots and dashes of the Morse code. 
But how to construct transmitting apparatus that would 
project electromagnetic waves capable of reproducing 
the complex sound vibrations of the human voice was a 
baffling problem. But baffling problems are not coimted 
as insurmountable obstacles in these days and scientists 
everywhere began the search for a wireless telephone. 

The first approach to the solution of the problem was 
made by two Englishmen, Simon and Duddell. In 1897, 
only a year after Marconi's great success with the wireless 
telegraph, Simon discovered the phenomenon of the speak- 
ing arc. This discovery was the basis of the early systems 
of wireless telephony and is to-day the principle upon which 
many of them operate. Simon found that if he connected 
a simple microphone circuit across the terminals of an 
electric arc and then spoke into the microphone, (the alter- 
nating currents set up would so affect the arc current as 
to reproduce the sound. The microphone, which is an 
ordinary telephone transmitter, may be at a considerable 
distance from the arc with excellent results. The use of 
this apparatus became a favorite demonstration with 
popular lecturers. There was nothing wireless about it 
but the fact that small alternating currents set up by the 

124 



Talking Through the Ether 125 

impulses of the human voice could so impose themselves 
upon another circuit as to reproduce sound vibrations 
and intelligible speech led to important results. 

The simplest form of speaking arc will be understood 
from the diagram in Fig. 51. 

The transmitter is at T, a battery at B, the arc at A and 
at C and C are choke coils which choke back the alter- 



H irsinr 



C 

JULSJL 



B 






Fig. 51. — The speaking arc. 

nating currents from the microphone circuit and confine 
them to the arc. 

Duddell improved the apparatus by placing an ordinary 
telephone induction coil or wireless transfomer and a con- 
denser in the shimt circuit for the production of the alter- 
nating currents. 

Now the problem of wireless telephony was to produce 
at the transmitting station and radiate into space a con- 
tinuous sustained train of electromagnetic waves upon 
which could be imposed through the sound waves of the 
human voice variations capable of being reproduced as 
sound waves in a distant telephone receiver. In a wireless 
telegraph transmitter the waves produced by the spark 
discharge are not continuous, but intermittent and there- 
fore some other means of generating these waves had to 
be devised. For this purpose Poulsen, a Danish investiga- 
tor, who bears much the same relation to wireless telephony 



126 



The Boys^ Own Book of Great Inventions 



that Marconi does to wireless telegraphy, adapted the 
vibrating arc already mentioned. 

How Poulsen made an electric arc generate a sus- 
tained oscillating current and maintained a continuous 
electric oscillation of the aerial will become clear from the 



rywm 



A 



\_W\Mk 
R 




Fig. 52. — Apparatus for producing continuous electric oscillations. 

diagram in Fig. 52. A direct current generator sends a 
current through ordinary electric Hght carbons producing 
an arc at A. Resistances to control the current arc placed 
at R and R' and choke coils at C and C. An inductance 
coil is placed at L and a condenser at K. Now as the current 
flows through the arc, the condenser K at the same time 
becomes charged, diminishing the current through the arc 
but increasing the voltage across it. This serves to charge 
the condenser still more which, when fully charged, begins 
to discharge through the arc and inductance coil. But 
just as the Leyden jar charges itself in the opposite direc- 
tion so does this condenser and it continues to charge and 
discharge as long as the current and arc are maintained. 
Thus it will be seen that a continuous oscillatory current 
is set up which, if an antenna were provided, would radiate 



Talking Through the Ether 127 

without interruption sustained trains of undamped elec- 
tromagnetic waves. 

This was just what was needed for wireless telephony 
and Poulsen's next step was to provide an antenna and 
microphone transmitter. As shown in Fig. 53, the trans- 
mitter was connected to the ground on one side and to 
the antenna circuit on the other. The action is as follows : 
The high frequency oscillations of the arc circuit induce 
corresponding currents in the antenna which gives a con- 
tinuous radiation of electromagnetic waves. Now as one 
speaks into the transmitter the vibrations of the voice 
modify these radiated waves, and when they are received 
by a distant aerial and pass through the detector circuit, 
the telephone receiver reproduces the original sound waves. 
The receiving apparatus is exactly similar to that used in 
wireless telegraphy. 

Shortly after this Poulsen increased the efficiency of 
transmission by using a water-cooled copper anode and 
by placing the arc in an atmosphere of hydrogen gas or a 
hydrocarbon vapor. With this outfit he was able to tele- 
phone for distances of several hundred miles and the wire- 
less telephone became a commercial possibility. 

Other investigators, notably, Colin and Jeance of France 
and Dubillier, Collins and DeForest of this country have 
experimented with the arc telephone. High frequency 
spark transmitters have also been devised but among the 
most important inventions are the ^'Audion Amplifier" 
and '^OsciUion Bulb'' of Dr. Lee DeForest. The former 
was an important factor in the perfection of the trans- 
continental wire telephone and both have played an im- 
portant part in the very remarkable recent triumphs of 
wireless telephony. The Audion Amplifier connected in 
a wireless receiving set is shown in Fig. 54. It consists of a 



128 



The Boys' Own Book of Great Inventions 






> 



'at 



mmm) 



mmMb — ^ 



S 



bo 
.5 

*> 

*8 

a> 
§ 

"a; 



^ 



mmmh 



■9y 



Talking Through the Ether 



129 



small incandescent lamp bulb exhausted of air, and con- 
taining in addition to the usual filament a thin nickel plate, 
and between this and the filament a nickel wire bent grid- 




FiG. 54. — The DeForest Audion Amplifier. 

shaped. The filament is kept in a state of incandescence 
by a separate source of electricity. Although the bulb is 
exhausted it is not a perfect vacuum and the hot, but 
highly rarified gas left in it acts as a conductor for the 
batter}^ current from the cold plates to the hot filament. 
This results in a stream of negatively charged "ions" from 
the filament to the plate. But any voltage impressed on 
the nickel grid from the incoming telephonic currents ar- 
rests this flow and strange as it may seem a unit charge 
on the grid has an effect upon the battery and receiver 
circuit of from six to ten times that value. Therefore, we 
have the wonderful amplifying power of the bulb. Other 
vacuum bulbs of a similar nature both for transmitting 
and receiving have been devised by DeForest and also 
by Marconi, the General Electric Company, the Western 
Electric Company and the engineers of the American 
Telephone and Telegraph Company. 

Not satisfied with having estabHshed a transcontinental 



130 The Boys^ Own Book of Great Inventions 

telephone system, John J. Carty of the American Tele- 
phone and Telegraph Company, gathering about him a 
staff of brilliant American engineers, set out to achieve for 
America the honor of long distance wireless telephony. 
With the researches of DeForest and other inventors at 
their disposal, coupled with true genius in their own ranks, 
this group of engineers pushed rapidly forward, speaking 
over constantly increasing distances until on Sept. 29th, 
1 9 15, the world witnessed the most remarkable success of 
radio commimication. From his desk at 195 Broadway, 
New York, Theodore Vail speaking into an ordiaary trans- 
mitter was connected at Arlington, Virginia, with wireless 
telephone apparatus attached to the aerials of the U. S. 
Naval Station. Radiating from there in all directions with 
the velocity of Kght, a part of these electromagnetic waves 
were caught by the antenna of the wireless receiving station 
at Mare Island, California, and amplified so that John 
Carty could hear the voice of Mr. Vail and converse with 
him as easily as though they were in adjoining rooms. 
And not only this, but on the following day messages sent 
from the Arlington tower were heard at the wireless re- 
ceiving station at Pearl Harbor in the Hawaiian Islands, 
a distance of nearly five thousand miles. Messages were 
also received at San Diego, California, and at Darien on 
the Isthmus of Panama. A little later with receiving ap- 
paratus installed at the Eiffel Tower, Paris, men talked 
across the Atlantic. 

It is possible now to telephone by wireless from shore-to- 
ship and ship-to-shore and the time is at hand when a 
person sitting in his office may be connected at any coast 
city with wireless apparatus and talk with passengers on 
transoceanic liners. The practicability of the wireless 
telephone was demonstrated by the Navy Department 



^ ti 


H 


m^ 


w m 


v^^Hhhi^ 


mi 


[| |fl^ 


1 


mm 





Talking Through the Ether 131 

in May, 19 16, when it placed itself in communication with 
every navy yard in the United States. That the wireless 
telephone will ever come into serious competition with 
wire systems is not probable. The cost of installation and 
operation would be prohibitive and with millions of mes- 
sages passing simultaneously in all directions the necessary 
privacy of communication and freedom from interference 
could not be obtained. As a supplement to wire systems 
and for oceanic service it undoubtedly has a great field of 
usefulness. The commercial possibilities of the wireless 
telephone are as yet almost wholly undeveloped. Great 
progress is being made in its use, however, by the Army 
and Navy Departments of the government and at the close 
of the war we may confidently expect even greater achieve- 
ments in radio comniunication than the marvelous triumphs 
of the past. 

In one very important way the development of wireless 
telephony will differ from that of the wireless telegraph. 
The latter was and always will be preeminently the province 
of the amateur. But the cost as yet of building and operat- 
ing over any considerable distance a reliable radiophone 
is beyond the reach of most amateurs. As Professor Alfred 
N. Goldsmith, one of the world's greatest radio experts, 
says, ^'the average amateur might just as well not attempt 
to construct such sets in the present state of the art." 

This does not prevent, however, one or two experiments 
and the construction of a simple wireless telephone that 
will operate over short distances. 

The Talking Arc Light. — If a source of direct current is 
available so that a carbon arc Hght can be maintained the 
apparatus for the talking arc may be arranged as shown 
in Fig. 55. If possible a hand feed arc lamp should be pro- 
vided for the carbons, but if this is impossible some other 



^ 




q 



132 The Boys^ Own Book of Great Inventions 

arrangement can be devised. A resistance at R great 
enough to cut the voltage across the arc to 50 volts should 
be provided. For this use the rheostat described under 

(the heating effects of the 
current in the chapter on 
/ electricity. 

f\ At C is a choke coil. 
The core for this may 
be made from hay wire 
cut into pieces about six 
inches long and bound 
into a bundle % inch in 
^^^- •55- diameter. Wind this over 

with three layers of binding tape and upon this insulation 
wind 7 layers of No. 12 double covered cotton magnet 
wire. Leave out tapes from the 4th, ^th and 6th layers to 
permit of adjusting the inductance. 

Now across this choke coil shunt an ordinary carbon 
telephone transmitter with a switch in series. This may 
be at a considerable distance from the arc if desired. Speak 
into the transmitter and adjust the amount 01 inductance 
in the choke coil by connecting to the different tapes until 
the soimd produced by the arc is loudest and most distinct. 
A Simple Wireless Telephone. — Provide an aerial the 
same as is used in wireless telegraphy and an electric arc 
as in the previous experiment. The source of current 
should be alternating and 60 cycles, 1 10 volts. Choke coils 
consisting of 60 turns each of No. 10 double covered cotton 
magnet wire are placed at C and C. The transformer T 
may be an ordinary step-up wireless transformer. The 
carbons should leave only a minute gap at G. The con- 
densers at K and K' are made like those for wireless teleg- 
raphy using in each 4 plates of glass 9 by 11 inches with 



Talking Through the Ether 



133 



tinfoils between. The oscillation transformer T' may be 
the same as that used in any simple wireless set. At M 
place an ordinary carbon transmitter. 

Now tune the current until oscillations are set up which 
can be determined by placing a small glow lamp across the 



V 




Fig. 56. 

secondary of the aerial transformer. This will light when 
the proper amount of current is flowing through the pri- 
mary of the step-up transformer. During this adjustment 
disconnect the aerial and ground. 

The receiving set may be the same as that used in wire- 
less telegraphy and the two sets must be tuned into res- 
onance with each other. Over short distances such a wireless 
telephone will give very satisfactory results. 



Chapter VIII 
THE STORY OF AVIATION 

As I began to write this chapter on the achievements of 
aviation the very loud hum of motors and an unusual 
commotion outside called me to the street and looking up 
I saw, but a short distance above, the largest dirigible it 
has ever been my pleasure to observe. Like a huge bird 
conscious of its power and majestic in its movements this 
man-made craft rose and fell, turned whither it would or 
hovered over a single spot with all the grace and ease of its 
feathered superiors in the art of aerial navigation. And 
as I watched, there came fluttering down, what at first 
glance looked like a flock of white winged doves, but as 
one of the naissives dropped at my feet I picked it up and 
on it read this inscription: 

"This copy of the ^Star Spangled Banner' v/as dropped 
by United States aviators flying over more than 100,000 
foreign-born citizens as they paraded on Fifth Avenue, 
New York City, in a great pubKc pledge of loyalty to the 
nation, July 4, 1918. Every race and every nationality 
was represented. Regiments of American sailors, American 
soldiers and United States marines led the marchers while 
the nation's progress in the war was pictured on great 
floats." 

Followed by aeroplanes this aerial demonstration is a 
fitting symbol of that supremacy in the air which more 
than anything else may be a decisive factor in the tremen- 

134 



The Story of Aviation 135 

dous struggle for human freedom and the future of civiliza- 
tion. When we recall that less than two decades ago real 
mastery of the air was apparently an iridescent dream, 
the actualities of the present remind us once more that 
the ''impossible" is forever giving way before the inventive 
genius of the race. Under the spur of military necessity 
the science of aviation has ceased to be a sport and become 
in an incredibly short space of time one of the most formid- 
able weapons in the grim business of war. The but recently 
established mail routes are only a forecast of the tremendous 
commercial possibilities of the future. Even now trans- 
atlantic aeroplane service seems entirely practicable and 
tomorrow it will be a fact. Out of this holocaust of war 
the world is surely moving forward and inventions are 
being perfected which will be of the utmost importance to 
industrial development when the nations of the earth 
*' shall beat their swords into plow-shares" and return 
once more to the pursuits of peace. 

To conquer the atmosphere and to be able to glide through 
it at will with the ease and perfection of the birds of the 
air has always had a wonderful fascination for the imagi- 
nation of the race. The one essential element lacking in 
man's physical equipment has seemed to be wings. The 
angels in heaven are pictured as possessing the power of 
flight and from the Middle Ages come fanciful tales of 
sorcerers and magicians who likewise were endowed with 
this supernatural gift. But until very recently flying has 
been regarded as the most fitting symbol for the utterly 
impossible. When we have wished to express our com- 
plete disbehef in the success of any project we have said, 
''it is as impossible as flying." But in every century there 
have been rare spirits who persisted in dreaming of the 
possibility of mechanical flight and once more these dream- 



136 The Boys^ Own Book of Great Inventions 

ers have had their way. The visions of the past are the 
reahties of the present and one more step has been taken 
toward the annihilation of space and time. 

That human beings should ever be able to devise means 
of lifting themselves into the great ocean of air at whose 
bottom they Hve seemed too absurd for serious considera- 
tion. Seemingly weightless it was known that the atmos- 
phere possessed 15 pounds pressure per square inch and 
although apparently non-resistant it could drive ships 
over the sea and do the utmost violence to trees and build- 
ings in the fury of a storm. That a given volume of air 
actually had a definite weight was known to such scientists 
as Cavendish, Black and Priestly. Cavendish, too, in 1766 
had done important work on hydrogen gas, which he called 
inflammable air, and had shown that it weighed about one- 
fourteenth as much as an equal bulk of real air. An ItaHan, 
Tiberius Cavallo, had made toy-ballons inflated with 
hydrogen. But the honor of first making an actual balloon 
of considerable size and Hfting power belongs to the Mont- 
golfler brothers of Annonay, France. Knowing nothing 
of hydrogen gas, these experimenters made use of hot air 
and inflated their gas bag by building a fire underneath 
and filling it with the hot products of combustion. After 
succeeding with several small balloons they made a large 
gas bag from Hnen and paper having a diameter of 35 feet 
and a capacity of 23,000 cubic feet. This rose to a height 
of 1000 feet and traveled a distance of a mile. On June 5, 
1783, the Montgolfiers gave a public demonstration before 
a large audience of thoroughly skeptical observers. When, 
however, the balloon carrying a weight of 300 pounds in 
its bag and frame shot into the air and rising to a height 
of 6000 feet traveled a mile and a half with the wind, ex- 
citement and enthusiasm knew no bounds. Paris went 



The Story of Aviation 137 

balloon mad and by public subscription raised money to 
defray the cost of further experiments. 

Shortly after this a Frenchman named Charles filled a 
balloon of 22,000 cubic feet capacity with hydrogen using 
498 pounds of sulphuric acid and 1000 pounds of iron filings 
to generate the gas. The ascension was made on August 
27 th of 1783. In a few seconds the balloon rose to a 
height of over 3000 feet and then disappeared in the clouds. 
Three-quarters of an hour later it fell in a distant field 
much to the amazement and terror of the natives who 
attacked it as a new monster of flight, and tying the bag 
and frame to a horse's tail sent tlie horse galloping across 
the country. 

Rozier, another Frenchman, was the first man to ascend 
in a balloon and in the first two years of aerial navigation 
at least fifty persons made more or less extended voyages. 
In attempting to cross the Channel to England, the brave 
Rozier lost his Hfe. The balloon was driven back toward 
the land and, the gas bag taking fire, he was dashed to the 
ground. In the French Revolution balloons were first 
used for miHtary purposes. Napoleon took several with 
him on his expedition to Egypt and in the battle of Fleurus 
General Jourdain was furnished valuable information of 
the Austrian positions by balloon scouts. In 1797, Gamerin 
invented the parachute, and in 1823, George Green of 
England utilized coal gas instead of hydrogen for the in- 
flation of the balloon, which, though not having so great 
a lifting power, was much cheaper. Ballooning became 
a popular sport. Later in the Crimean War, in the Civil 
War and in the Franco-Prussian War of 187 1, the balloon 
demonstrated its mihtary importance. When Paris was 
besieged in 187 1 its only means of communication with 
the outside world was by balloons. During the siege the 



138 The Boys^ Own Book of Great Inventions 

inhabitants of the beleagured city sent out 64 balloons 
carrying 155 persons and more than 3,000,000 letters. 

In the Great War of today captive, or kite-balloons, 
anchored by a rope to the ground are of immense impor- 
tance. The elongated gas bag of such a balloon is four-fifths 
filled with hydrogen and the remaining one-fifth of the space 
is occupied by a small bag called the ballonnet, which is 
filled with air. This is automatically inflated by pumping 
air from the outside and maintains a constant pressure 
within the gas bag. When, through changes of altitude or 
temperature, the inside pressure exceeds a certain value, a 
valve opens and allows air to escape from the ballonnet 
until the pressure has been reduced to the proper amount. 
As the reverse pressure change occurs air is automatically 
pumped into the ballonnet. 

On the Western front hundreds of these captive balloons 
dot the rears of the Allied and German positions. In the 
basket slung beneath the gas bag officers with field glasses 
and telescopes observe the enemy positions and direct the 
artillery fire of their own guns. These men are provided 
with parachutes to insure a safe escape in case of attack. 
Such balloons are superior to aeroplanes for this work be- 
cause of their ability to hover over a single spot. Just 
preceeding the great battle of the Somme in 19 16, the Allies 
sent fighting aeroplanes to attack the German observation 
balloons and drive them from the air before beginning the 
big drive. 

The Dirigible. — ^The typical balloon, however, simply 
drifts with the wind and is at the mercy of every gust that 
blows. While a great achievement and of much practical 
importance, nevertheless the balloon did not satisfy, but 
only stimulated, man's intense longing really to navigate 
the air. The aeronaut's supreme ambition was to direct his 



The Story of Aviation 139 

own course and to imitate so far as possible the movements 
of the birds. Ahhough numerous experimenters had for at 
least three centuries endeavored to perfect birdlike mech- 
anisms capable of actual flight, after the advent of the 
balloon, the surest means of success seemed to lie in some 
sort of dirigible balloon. But it took a century to work out 
the requirements for complete success. The ballonnet, the 
stabilizing fins, the horizontal rudder and the gasoline engine 
were prime essentials, and at last they came. 

The first real successful attempt at the construction of a 
dirigible balloon was made by Henri Giffard of Paris in 
1852. He adopted the familiar cigar-shaped gas bag so 
common in later construction and beneath it suspended a 
steam engine that drove a screw propeller. The envelope 
contained 90,000 cubic feet of coal gas, being 150 feet long 
and 40 feet in diameter. With this dirigible he was able to 
make 7 miles an hour against a strong wind and by means of 
a rudder succeeded in steering it in any desired direction. 
Although a great success, Giffard abandoned aeronautics 
and nothing further was done for more than a quarter of a 
century. 

Numerous other attempts were made during the last 
quarter of the nineteenth century but not luitil the advent 
of the young Brazilian, Santos-Dumont, in 1898 was any 
real progress made. He had come to Paris with great 
wealth and an immense fimd of enthusiasm to devote his 
genius and intense energy to the science of aeronautics. 
Just at this time, too, came the automobile with the wonder- 
ful development of the gasoline engine. The elements of 
success were now at hand and no greater enthusiast has 
ever appeared than Santos-Diunont. In rapid succession 
he built six Hght fragile dirigibles, each driven by a gasoline 
motor and with the last he won the prize of 100,000 francs 



140 The Boys^ Own Book of Great Inventions 

offered by M. Deutsch to the aeronaut who should success- 
fully round the Eiffel Tower and return to the specified 
starting point in half an hour. On October 29th, 1900, 
Santos-Dumont accomplished the feat in 29 minutes and 
30 seconds to the admiration of the gaping thousands who 
watched the flight with the keenest interest. 

In the meantime Count Zeppelin of Germany had been 
working on his now famous leviathans of the air. These 
immense airships bore about the same relation to the 
*' cockle-shell" dirigibles of Santos-Dumont that an ocean 
liner bears to a tug boat. The ZeppeKn, although the same 
in principle as Giffard's dirigible, represents several radical 
departures and in point of efficiency the two are as far apart 
as the stage coach and the modern express train. Instead 
of maintaining the shape of the hull by a gas pressure inside 
the envelop superior to the atmospheric pressure outside, 
the Zeppelin makes use of a rigid framework covered with 
fabric which encloses a comparatively large number of 
drum-shaped gas bags. These gas bags are filled with 
hydrogen and because of the immense size of the craft their 
lifting power is very great. If one or even several of these 
compartments are destroyed the lifting power and ability 
to continue the journey are only partly impaired. The 
gasoline engine, without which successful air navigation 
would be utterly impossible, is of course used. The first 
Zeppelin built was 30 feet in diameter, 400 feet long and 
had 17 gas compartments. The company that built it was 
capitalized at $200,000 and the cost of the shed for housing 
it was $50,000. The latest Zeppelins are 650 feet long and 
are driven by six 250 horsepower motors. 

The Zeppelin, like the baUoon, floats in the air because 
the weight of air displaced by it is equal to the weight of the 
Zeppelin and contents. If it rises it is because the weight 



The Story of Aviation 141 

of air displaced exceeds that of the Zeppelin and just as a 
stick thrust beneath the water will rise, so will the Zeppelin. 
The balloon or Zeppelin will continue to rise until its average 
density, or weight per cubic foot, is equal to that of the sur- 
rounding air. If the balloon is to rise, ballast, either sand or 
water, is thrown overboard. This lowers the average 
density and the balloon shoots upward. When the balloon 
is to descend gas is allowed to escape by opening a valve in 
the gas bag. In the case of the Zeppelin there are air bags 
in the compartments as well as hydrogen drums. The two 
are in direct contact so that the pressure of one reacts 
directly on that of the other. Now if the Zeppelin is to 
rise hydrogen is pimiped from steel containers into the 
hydrogen drums and at the same time air is forced out of the 
air bags. Since hydrogen is fourteen times Kghter than 
air this increases the buoyancy and the Zeppelin rises. 
When the Zeppelin is to descend hydrogen is pumped back 
into the steel compression tanks and air at the same time 
is forced into the air bags. These changes can be effected 
very quickly and rapid movements thereby executed. In 
addition the Zeppelin carries elevating rudders Hke an 
aeroplane and can use them for quick movements, but to 
remain permanently at a higher or lower level the density 
of the airship must be made equal to that of the air outside. 
Although a Zeppelin weighs 20 tons, its size is so great and 
hydrogen so Kght that it navigates the air with perfect ease. 
A ZeppeHn starts at an altitute of 5000 feet, but by the time 
it has traveled from Berlin to London say, its consumption 
of fuel has so decreased its weight that it has risen several 
thousand feet higher. One very disconcerting feature to 
gunners operating anti-ZeppeHn guns is the fact that after 
the dropping of each bomb the Zeppelin, lightened by the 
loss of ballast, immediately rises about 200 feet. The max- 



142 The Boys^ Own Book of Great Inventions 

imiun altitude for Zeppelin navigation is said to be io,cxx) 
feet. Balloons, however, have risen to altitudes of seven 
miles. 

The flight of the first Zeppelin was a failure, but the 
Zeppelin II, the fifth creation of Count Zeppelin, on May 
29th, 1909, made a successful voyage of 850 miles. Before 
the war large air-liners carrying 24 persons and fitted with 
a luxurious cabin and restaurant were engaged in passenger 
service. 

At the same time, the German government created the 
air-cruiser for military purposes. In 191 2, the first of 
these huge naval air-craft on a trial trip covered a distance 
of 1,200 miles carrying a crew of 31 and a wireless outfit 
having a range of 200 miles. At the beginning of the war 
Germany had a fleet of a dozen of these high speed, long 
range Zeppelin cruisers. To offset them the Allies had 
only a few pressure air ships lacking both in speed and 
range. But in a short time the development of the bombing 
aeroplane and the anti-aircraft gun had destroyed the 
usefulness of the Zeppelin for scouting purposes and con- 
fined its operations to the nighttime. 

The earlier t3^e of dirigible pressure air-ship has proved 
very useful in anti-submarine defense, mine sweeping and 
some minor scouting operations. When the war is over, 
however, this type will undoubtedly give way to the rigid 
ZeppeHn, which seems capable of great conomercial develop- 
ment and to be especially well adapted to transatlantic 
service. 

.The Aeroplane. — But the dirigible did not really conquer 
the fields of air. The ardor, the peril and the joy of the 
aviator had not been experienced. To fly like the birds 
with a heavier-than-air machine and to rise to a complete 
mastery of the elements of space was the real aspiration 




An early Wright biplane; and a Zeppelin flying over Lake Constance. 



The Story of Aviation 143 

of every true aeronaut. The close of the last century and 
the first decade of the present witnessed very remarkable 
advances in this direction, but four years of war have 
brought results beyond the dreams of the most ardent 
enthusiasts. Truly the heroes of the air have come into 
their own and like the Vikings of the sea their daring ex- 
ploits will be told in song and story through the centuries 
to come. 

There was the example of the birds, weighing a thousand 
times more than the air displaced by them and yet flying 
with perfect ease. The flight of large birds, soaring and 
gHding with outstretched wings for hours without the quiver 
of a muscle, so far as could be observed, was and still is 
very largely a mystery. But if birds could fly why not 
men? And numerous were the attempts to accomplish 
this difficult feat. Helmholtz ''demonstrated" that man 
does not possess the muscular strength to propel himself 
through the air by the flapping of artificial wings and so 
far no one has succeeded in doing this, though it would 
be unwise to predict that it never can be done. 

That there is a vast difference in the Hf ting power of still 
air and air in motion is a matter of common experience. 
Any mass of matter, no matter how light, when in motion 
possesses energy and the abiHty to do work. One of the 
commonest examples of this is the ordinary kite. In the 
presence of a stiff breeze a boy may stand in his tracks 
and as he pays out string his kite, though many times 
heavier than air, mounts skyward. If there is no wind 
he well knows that he can make one by running forward 
with the kite-string and that just as before the kite will 
rise. 

More than a century ago. Sir George Cayley, an English- 
man, worked out the principles upon which the modem 



144 The Boys^ Own Book of Great Inventions 

aeroplane operates. In 1846, Stringfellow, another English- 
man, constructed a model aeroplane run by a steam engine 
which made several successful flights. In 1866, Wenham, 
also of England, developed the multiple surface aeroplane 
and Stringfellow embodied the principle in a successful 
triplane. In 1894, Sir Hiram Maxim built a heavier- than- 
air machine weighing about 4 tons and driven by screw- 
propellers operated by a 360 horsepower steam engine. 
In a trial flight this huge machine actually succeeded in 
leaving the ground and going a distance of 300 feet. It 
demonstrated the possibility of mechanical flight but Httle 
more. 

About this time Professor S. P. Langley, Secretary of 
the Smithsonian Institution, built a wonderfully successful 
little model. The width of the wings was 1 2 feet, the length 
of the machine 16 feet and it was driven by a steam engine 
which developed one and one-half horsepower and weighed 
only 26 ounces. The totaL weight of the machine was 31 
pounds. When given a trial, this model aeroplane rose 
in the face of a strong wind to a height of 100 feet and 
traveled a distance of three-quarters of a mile, coming to 
rest only when its steam was exhausted and then gliding 
gracefuUy to the earth. In 1903, Professor Langley built 
a steam driven man-lifting machine, but a defective launch- 
ing device resulted in plunging it into the Potomac river. 
Professor Langley gave up the task but following his death 
shortly after this, his machine was unearthed and made 
to fly. 

In the meantime Otto LiHenthal m Europe and 0. Chan- 
ute in this country had been making extensive experiments 
with gliders. A ghder is simply an aeroplane without 
motive power and LiHenthal constructed nimierous gliders 
having correctly curved surfaces made of linen stretched 



The Story of Aviation 145 

over light wooden frames. His first machine had a total 
area of about 14 square yards and weighed 40 pounds. 
In the center was an opening for the operator to stand hold- 
ing the machine in his hands. Lilienthal had given close 
study to the movements of the birds and he had observed 
that a soaring bird having once alighted could not raise 
himseK into the air without making an initial run to ac- 
quire the necessary speed. Adopting this method he began 
his practice flights by running down a gently sloping hill 
against the wind. When he had gained the necessary 
momentum he would let himself go with the result that 
he could gHde slowly and easily toward the foot of the hill. 
The front of the plane was inclined upward a few degrees 
to catch the wind and the pressure of the air as it slid be- 
neath the canvas surface gave supporting power to the 
machine. The initial run and the weight of the operator 
take the place of the string in the kite and the motor in 
the aeroplane. 

LiHenthal, learning by experience, constantly improved 
his machine, acquiring great skill in maintaining his equi- 
librium and in one flight succeeded in gliding a distance of 
1,200 feet. At times he could rise above his starting point 
and when wind conditions were favorable he could sail 
from a hilltop without the initial run. Unfortunately he 
met his death by a fall from his ghder in 1896, but the 
carefully preserved record of his work was of great assistance 
to his successors and he must always be remembered as a 
pioneer of aviation. 

But the news of the death of Lilienthal stimulated two 
unknown brothers in an Ohio town to study and investigate 
the possibilities of mechanical flight. All the world has long 
since come to know Wilbur and Orville Wright of Dayton, 
Ohio, as the inventors of the first man-carrying, motor- 



146 The Boys' Own Book of Great Inventions 

driven aeroplane. Their interest in aeronautics began 
when as lads their father brought home to them one night 
a small helicopter e flying machine. Later they read of the 
work of Lilienthal and Chanute and began making experi- 
ments with gliders of their own construction. Like every 
great invention success came only after years of patient 
research and persistent effort. History scarcely records a 
great achievement won at a larger cost of painstaking and 
exhaustive experimentation. They were compelled to de- 
velop for themselves the fundamental principles of aero- 
nautics, and the unreliable data upon which all flying ma- 
chines had previously been based caused them much 
unnecessary work. During this period, however, they 
were not forced to work in poverty, for a successful bicycle 
repair business kept them suppHed with funds. Their 
plan was to read and experiment during all their available 
spare time and then each autumn to spend several weeks 
on the bleak, windswept sand dunes at Kitty Hawk, North 
CaroKna, in actual gliding and flying. Increasing success 
marked the progress of their work, and by the autumn of 
1903 they had mastered the elementary principles of flight 
and given to the aeroplane the one missing link essential to 
self-controlled equihbrium. This was the warping mech- 
anism to prevent sidewise tipping and to keep the machine 
on an even keel. With such a machine they acquired 
greater skill than had ever before been exhibited in gliding 
experiments. 

The one thing now lacking for real sustained flying was 
a Hght reliable motor and this they proceeded to build. 
Being practical mechanics they built a gasoline motor of 12 
horsepower with a fuel capacity of a few minutes' duration 
and giving a speed of 30 miles per hour and installed it in 
their glider. Then on December 17th, 1903, in the bitter 



The Story of Aviation 147 

cold and raw winds of the Kitty Hawk sand dunes their 
first biplane carrying one of the brothers made a suc- 
cessful flight. For the first time in history a self-propelled 
flying machine lifted itself from the groimd with its own 
power and under the guidance of its pilot made a free flight 
and landed in safety. Four flights were made at that time, 
the last one having a duration of 59 seconds and covering 
850 feet. During these flights, too, they were not at the 
mercy of the wind but were able to steer their machine up 
or down or to the right or left as they chose. The flight by 
Sir Hiram Maxim had been an uncontrolled flight and 
ended with the first attempt. 

Only two years before, the great astronomer, Simon 
Newcomb, had stated that the construction of air craft 
that would carry even a single man ^'requires the discovery 
of some new metal or some new force. " But now the "im- 
possible" had once more been attained and as Wilbur 
Wright said, "the age of the flying machine had come at 
last.'' And yet the world knew practically nothing of the 
great achievement. One of the chief characteristics of these 
two men was modesty. Their experiments had not been 
carried on in secret but they had not been advertised. 
Very quietly they returned home and in 1904 and in 1905 
continued their flights at Dayton with two new machines. 
During this time 160 flights were made and the distances 
covered totalled as many miles. The last flight of 1905 
covered 24 miles and lasted 38 minutes. In this practice 
work the Wrights were patiently working out details and 
putting their machine under better control. The whole 
world will forever stand debtor to them for this groimd- 
work without which the marvelous present day success of 
aviation would be utterly impossible. 

The first Wright aeroplane obtained its Hfting power 



148 The Boys^ Own Book of Great Inventions 

from two horizontally placed parallel planes of canvas 
stretched over light wood frames and placed crosswise of 
the machine. In front were two horizontal parallel rudders 
for raising and lowering the machine in flight, and at the 
back two vertical rudders for sidewise steering. Two 
wooden propellers similar to ship-propellers were placed 
just back of the two main planes. The machine was kept 
on an even keel by the device for warping the ends of the 
planes and thereby changing the angle at which the air 
strikes them. This device is probably the most distinct 
contribution to the aeroplane mechanism made by the 
Wright brothers. In 1906, they obtained a patent on their 
machine and sought to introduce it to the world. 

The success of the aeroplane now became rapid and 
certain. The invention of a light powerful gasoline engine 
was a prime factor and the Wright warping device insured 
lateral control, which had hitherto been hupossible. Ex- 
perimenters were at work abroad, too, particularly in 
France. In 1908 Henry Farman, an Englishman living in 
Paris, aroused the enthusiasm of the French people and 
won a 2,000-franc prize by flying over a prescribed circular 
course, a distance of 1,600 yards, and returning to the start- 
ing place. The Wrights had more than four years before 
made more remarkable flights, but the world still remained 
in ignorance of them. In the autumn of 1908, however, 
Orville Wright in America and Wilbur Wright in France 
began a series of public demonstrations that electrified the 
world and forever settled the question as to whom belonged 
credit for having conquered the air. On September 12th 
Orville Wright at Fort Meyer, Virginia, flew continuously 
about a circular course for an hour and fifteen minutes. 
Nothing like it had ever before been witnessed and the 
whole world from that moment knew that mechanical 



The Story of Aviation 149 

flight was not only a possibility but a magnificent success. 
This great triumph was marred, however, by an accident 
a few days later which wrecked the machine and resulted 
LQ the death of Lieutenant Selfridge, a companion in flight 
of the inventor. This is the first death chargeable to avia- 
tion in a seh-propelled, heavier- than-air machiue. 

At the same time in France Wilbur Wright was convinc- 
ing the skeptical citizens of that country of his just claims 
to having conquered the air. He made numerous flights 
to the delight of the emotional and enthusiastic French 
public, in one of which he remained in the air for two hours, 
twenty minutes and twenty-three seconds. 

On July 19, 1909, Hubert Latham attempted to cross the 
Channel to England but when he had nearly attained his 
goal his motor failed and he plunged into the water, being 
rescued, however, without injury. Six days later on July 
25th, Louis Bleriot flying in a small monoplane succeeded 
in making the passage. In this same month Orville Wright 
met the endurance test of the United States Government 
by flying for more than an hour with a passenger in the 
machine. Later in this year he made a number of flights 
in Berlin demonstrating the superiority of the aeroplane to 
the unwieldy Zeppelin. In October of 1909 at the Hudson- 
Fulton Centenary Celebration Wilbur Wright made a 
spectacular flight from Governor's Island over the war- 
ships anchored in the North river up the Hudson and back 
to the starting point. 

The Wright brothers now received the honor which was 
their due. They were decorated by the crowned heads of 
Europe and awarded medals by many scientific societies, 
aero clubs and universities, by the Smithsonian Institution, 
the City of Dayton, the State of Ohio and by Congress. 

Another aeroplane inventor who has done much notable 



150 The Boys' Own Booh of Great Inventions 

work and of whom all Americans are justly proud is Glenn 
H. Curtiss. A yoimg bicycle mechanic, he early began the 
study of aeronautics and in August of 1909 with a biplane 
and 8-cylinder engine of his own construction won the chief 
speed contest in the International Aviation meet at Rheims. 
In the following spring he further distinguished himself by 
making a flight from Albany to New York, covering a 
distance of 14272 miles in 2 hours and 54 minutes, at an 
average speed of 50 miles an hour and with only one stop. 
Since then he has made many notable flights and has done 
very important work in the development of aeroplane con- 
struction, his most important contribution being the "fly- 
ing boat,'' a sea-plane for use in naval warfare. The Cur- 
tiss Engineering Corporation of Buffalo is one of the largest 
aeroplane plants in the country. 

To complete the aeroplane romance and tell the story of 
the remarkable development between 1909 and the out- 
break of the great war would require a volume in itseK. 
During this period the chief object of aviation was sport. 
The commercial and mihtary usefulness of the aeroplane 
were seen, but little real development in these directions 
was made. And yet the progress made in these years was 
fundamental to the great success of military aviation in the 
years immediately following. The mastery of mechanical 
details and preeminently the improvement of the gasoline 
engine were vital factors. To the Voisin and Farman 
brothers the world owes the development of the pusher 
biplane and to Louis Bregnet and A. V. Roe the tractor 
biplane. The Seguin brothers of France invented the 
famous Gnome engine which has done more for the prog- 
ress of aviation than any other one invention. Aeroplane 
engines weighing but Httle more than two pounds per horse- 
power are in common use. The power of these engines is 



By courtesy of Scientific American 

Hydroplane dropping depth-bomb on a submanne. 



The Story of A viaiion 151 

much higher than that used in the early machines, giving 
much greater speeds and making possible the use of smaller 
planes. Several modern engines are shown in accompany- 
ing cuts. 

Military Aviation. — At the outbreak of the Great War 
the possibilities of the aeroplane in military operations were 
but Httle known. Its chief use up to this time had been 
for scouting purposes and it is now perfectly evident that 
none of the belligerents had any adequate conception of the 
tremendous part that aviation would play in the winning of 
the great conflict. But from the very start the aeroplane 
has demonstrated its immense usefulness At the battle 
of Mons an aviator saved the British expeditionary force 
from annihilation by reporting that the Germans had 
much larger numbers than had been anticipated. It was 
another aviator at the decisive battle of the Marne who 
made known the gap between Von Bulow's and Von Han- 
sen's armies and enabled General Foch to compel a German 
retreat by driving a wedge into their lines. These and 
many other instances firmly established the great value of 
aerial scouting and each side began to study the art of 
aviation as never before and prepared to make vast addi- 
tions to its aeroplane fleets. 

Perfection in aeroplane construction came with a rapid- 
ity never before equaled in any great invention. It was 
almost meteoric. The views of scientists and strategists 
were crystallized and put to test. The essential mechanism, 
however, of the early Wright models remained. No radical 
departure was made, but just as the steam engine of the 
forties evolved into the powerful high speed locomotive of 
the twentieth century, so did the aeroplane almost over 
night change into a powerful fighting machine. Strong 
imbreakable wings, a boat body enclosing crew, engines, 



152 The Boys^ Own Book of Great Inventions 

steering gear and tanks, together with engines of more than 
200 horsepower and developing speeds of 1 20 miles an hour, 
came in rapid succession. With increased power and speed 
any weather can be braved and the size of the wings to 
give the same lifting power can be decreased many times. 
The factor of safety has increased to nearly 100 per cent. 
Engine troubles are almost obsolete. Military officers fly 
freely over the Alps without any possibility of landing, and 
there is not the slightest doubt that by the spring of 19 19 
transatlantic service will be an accompKshed fact. 

The scouting aeroplane is a two seater of great speed range 
whose duty it is to observe enemy positions and movements 
and to report them immediately to headquarters. Its 
armament consists of a single defensive gun and its crew is 
composed of a pilot and trained observer. The height at 
which scouting planes fly must be above 6,000 feet in order 
to escape bullets from anti-air craft guns. At this altitude 
the observer must be able to distinguish a convoy train 
from artillery, howitzers from field guns, or a supply depot 
from a harmless landmark. He must also be able to operate 
an aeroplane camera and to manipulate a wireless outfit. 
The whole attention of the pilot is absorbed in steering 
such a zigzag course as to escape the fire of enemy aircraft. 
Even though riddled with bullets if the petrol tank and 
machinery remain intact these scouting planes will make 
a safe return. Besides making the usual observations these 
planes supply to the artillery the exact range of enemy 
objectives to be shelled. At headquarters the photographs 
are quickly made into lantern slides and thrown upon a 
screen by a stereopticon which brings out and greatly mag- 
nifies every detail. 

Very soon it became apparent that scouting planes must 
be afforded protection. It also became necessary to de- 



The Story of Aviation 153 

stroy kite-balloons and to drive off the scouting planes of 
the enemy. And for this purpose there was invented the 
high speed, single-seated tractor which can out-fly and out- 
manoeuvre any other type of machine. It will fly 130 
miles per hour and climb 1,000 feet per minute. The pilot 
operates a machine gun fixed rigidly in front of him and 
aims it by steering the aeroplane directly against the target. 
This necessitates shooting straight through the propeller 
blades, but a timing device connected with the gun makes 
it possible to fire bullets at the rate of 400 per minute with- 
out hitting the blades. This invention vital to the success 
of the fighting plane was made by the famous French air- 
man, Ronald Garros. These fighting planes also convoy 
bombing machines and frequently go in large numbers. 
When a fighting flotilla from either side seeks to secure 
mastery of the air the only way to combat the machines is 
by attacking them with other machines. And then ensues 
a battle royal, above the clouds it may be, where with 
dizzy manoeuvres and lightning Kke rapidity of movement 
the exploits of Paul Jones, Lord Nelson and Admiral Farra- 
gut are put into the shade. 

The bombing planes are the dreadnaughts of the air. 
The new Handley-Page plane described by Mr. John D. 
Ryan, head of the Aircraft Production Board, as ''one of 
the most powerful ever built" is equipped with two of the 
famous Liberty motors developing over 800 horsepower 
and wiU carry from a ton and a half to two tons of explo- 
sives. In fleets of sometimes 50 and 60 machines convoyed 
by high speed fighting planes these dreadnaughts make 
raids far over enemy lines dropping tons of explosives on 
airship sheds, supply depots, railway junctions, munition 
plants, submarine bases and coast defenses. Most severe 
punishment both moral and material is inflicted in this 



154 The Boys' Own Book of Great Inventions 

way, and it is safe to say that could either belligerent in- 
crease the number of its bombing planes to 15,000, without 
adequate means of defense on the part of the enemy, a 
complete victory would be won in less than three months. 
Such a fleet could drop 50,000 tons of high explosives upon 
the enemy every 24 hours and neither the physical endur- 
ance nor the morale of any nation could long withstand 
such terrific bombardment. If history ever records an- 
other surprise attack like the fell swoop of Germany in 
19 14, it will come through the air and woe be to the de- 
fenseless nation against whom the attack is directed. 

But for the promotion of domestic and foreign trade, 
social and political intercourse among nations and the 
breaking down of the barriers of time and space, this great 
conflict has forged an instrument more potent than any 
other invention in modem times. Even now no less an 
authority than Claude Graham-White freely predicts 
speeds of from 250 to 300 miles an hour. The international 
financier or statesman may transact business in New York 
and Washington one day and in London and Paris the next. 
Transcontinental aerial mail and express routes will sepa- 
rate New York and San Francisco by only twenty hours. 
Through passenger service, too, with every provision for 
comfort and safety will make the transit of the continent 
in even less time. The time and money thus saved in a 
single year will mount into colossal figures. This old earth 
suffering in rapid succession the offensives of the steam 
engine, the telegraph, the telephone, the electric motor, 
the wireless telegraph and now the aeroplane, the modem 
meteor of the skies, is rapidly dwindling into truly insig- 
nificant proportions. And just in proportion as men and 
nations are brought into more intimate relations the forces 
that make for peace and the prohibition of war multiply 



The Story of A viation 155 

and strengthen. Surely in this great service of the future 
the aviator will take high rank. 

How prophetic of present and future achievement were 
the words of Tennyson: 

"For I dipt into the future, far as human eye could see, 
Saw the Vision of the wodd, and all the wonder that would be; 
Saw the heavens fill with commerce, argosies of magic sails, 
Pilots of the purple twilight, dropping down with costly bales; 
Heard the heavens fill with shouting, and there rain'd a ghastly dew 
From the nation's airy navies grappling in the central blue; 
Far along the world-wide whisper of the south-wind rushing warm, 
With the standards of the peoples plunging through the thunder- 
storm; 
Till the war-drum throbb'd no longer, and the battle-flags were furPd 
In the Parliament of man, the Federation of the World." 



Chapter IX 
THE PRINCIPLES OF THE AEROPLANE 

How does it happen that a machine many times heavier 
than the air through which it moves does not fall? What 
sustains it? In a vague way we know that the air pressure 
does it. But how does there happen to be air pressure 
sufficient for such a gigantic task? To most people this 
whole subject is shrouded in more or less of mystery. And 
yet the explanation is not difficult to understand. 

The Kite. — We will start with a kite, which if flying in 
&till air with a boy and string for motor is a miniature tractor 
monoplane. When the air is still any boy knows that he 
must run Kke the wind if he is to succeed in lifting his kite 
off the ground. But presently as he increases his speed the 
breeze which he creates by his own running catches be- 
neath the inclined surface of the kite and it begins to rise. 
Now a kite is a heavier-than-air machine, and if it rises it 
must be that some force has been developed sufficient not 
only to support the weight of the machine but also to Hf t it 
against the force of gravity as well. And this force has 
come about by pulKng the kite plane rapidly through the 
air with its front edge raised a little so that the ''wind" 
will catch it. Evidently this artificial breeze has produced 
a pressure on the kite which in part at least has been up- 
ward and able to lift it. 

Now the most common property of all matter including 
the air is inertia. Inertia means inactivity. A body at 
rest tends to remain at rest or if in motion to continue in 

is6 



The Principles of the Aeroplane 157 

motion. And to every action there is an equal and opposite 
reaction. These are familiar laws of physics. If you hang 
a heavy weight from a hook in the ceihng, the hook pulls 
back with an equal and opposite force and if it did not the 
weight would fall. Strike the surface of a body of water a 
quick sharp blow with a long thin board and the water does 
not yield but acts like a solid. When you take a running 
jump the earth reacts against your feet and if it did not 
you could not leave the ground. When caught in a violent 
wind storm your body reacts against the rushing air and if 
the wind pressure proves too great you are driven before 
it hke a kite rising in a brisk gale. Could your body be 
supplied with a trailing appendage Hke the tail of a Idte so 
as to insure stabiHty you might easily be lifted skyward 
kite fashion. A column of natural gas issuing from a newly 
driven gas well frequently gushes forth with such high 
velocity and tremendous energy as to make it behave like 
a rigid solid. Give velocity to air and it possesses energy. 

Air at rest possesses inertia and when we strike it a sharp 
blow or pull a kite through it the tendency is to remain at 
rest and the air reacts exerting pressure on the surface. 
The amoimt of this pressure will depend upon the force of 
the blow or the speed of the kite. If we double the speed of 
the kite we will multiply the air pressure upon its surface 
by four, and if we treble it the pressure will become nine 
times as great. This is an important factor in aeroplane 
construction as we shall see later. The amount of pressure 
on a given kite will also depend upon its surface area. If 
we increase the area faster than we increase the weight we 
shall add to its Kfting power. 

Now the effective air pressure upon a kite or a moving 
plane is always at right angles to its surface and can be 
reckoned as so many pounds per square foot. The amount 



158 The Boy 5^ Own Book of Great Inventions 

of this pressure when the wind is blowing directly against 
a surface is equal, approximately, to the square of the wind 
velocity in miles per hour divided by 300. Thus, if we 
have a wind velocity against our kite of 30 miles per hour, 
the pressure on each square foot of surface will be 30x30 -j- 
300 = 3 pounds. And it makes no difference whether the 
wind blows against the kite or whether we run with the 
kite, this pressure at right angles to the surface will be 
developed. Incidentally we note again, too, that the 
amoimt of this pressure increases not simply in the same 
ratio as the velocity increases but as the square of the ve- 
locity. 

It is always possible to replace any given force with two 
other forces that wiU have the same effect as the single 
force. If you place a hook in the wall and pull not straight 
out but in a slanting direction the effect on the hook will 
be the same as though you were employing two forces — one 
straight out and one straight down at right angles to each 
other. If you suspend a weight from a cross bar and sup- 
port it by two cords placed at an angle to each other the 
effect is the same as though you employed a single vertical 
force equal to the weight itself. 

Bearing the above statements in mind let us consider 
the forces in Fig. 57. The line AB represents a kite beine 
drawn through the air in the direction of the arrow. Thg 
line DC represents the pressure perpendicular to the kite 
surface. No matter at what angle the wind strikes the kite 
the pressure exerted will always be at right angles to the 
surface. This pressure, too, may always be regarded as 
concentrated at a single point called the center of pressure. 
All the small pressures acting upon the surface due to the 
wind could be replaced by a single force equal to their sum 
and acting at this point. Now considering this perpendicu- 



The Principles of the Aeroplane 



159 



lar pressure as concentrated in the single force DC it is per- 
fectly clear that its effect is in two directions. It exerts a 
vertical lift along EC counteracting the force of gravity 
and a horizontal thrust along FC which is neutralized by 



-m- 




D "^ 









Fig. 57 — Forces acting on a kite. 

the kite string. If at any moment this vertical force just 
equals the force of gravity the kite, though moving for- 
ward with the nmning boy, will not rise but will simply 
stay at that level. If this force exceeds that of gravity and, 
therefore, is greater than the weight of the kite, the kite 
will rise. When it becomes less than the weight of the kite, 
the kite falls. How great this force is depends upon the 
velocity of the wind or the speed with which the kite is 
pulled through the air. It depends, too, upon the angle at 
which the kite strikes the wind. If the kite were horizontal 



i6o The Boys' Own Book of Great Inventions 

and the wind blowing in the same direction, i. e., parallel 
with it, there could be no pressure on its surface. 

The Aeroplane. — Now the explanation of the lifting power 
of an aeroplane is exactly the same as that for the kite. 
We simply substitute for the string and boy a gasoline 
motor and drive the plane through the air at a speed of 60 
miles an hour, say. Using the same diagram as for the kite, 
AB will represent one of the two main planes, DC the 
pressure developed perpendicular to the surface and FC the 
vertical component of this pressure which coimteracts the 
weight of the machine and lifts it upward. The horizontal 
component FC is the resistance which the propeller must 
overcome in driving the machine forward. In starting 
from the ground the two main planes are set so as not to 
catch the wind and the motor is started. The machine 
runs along the ground until sufficient speed has been at- 
tained when suddenly the pilot tilts the front edge of the 
plane upward to catch the wind and the pressure developed 
will immediately lift it from the ground and carry it into 
the air. Just as the soaring bird must run along the ground 
gaining considerable speed before it can spread its wings 
and mount upward, so must the aeroplane gain speed and 
pressure before it can fly. So, too, with the glider. Its 
operator runs with it to gain speed and then jimiping down- 
ward from some elevation, the pressure on the planes caused 
by the forward movement and the weight of his body, 
enable him to glide slowly and easily to a lower level. 

A popular way of explaining this gliding of an aeroplane 
is to say that the mass of air forced beneath the curved 
surface of the plane exerts an upward pressure tending to 
sustain the machine and that the forward movement is so 
rapid that the air literally does not have time to give way 
before it is replaced with a fresh mass. The effect is likened 



The Principles of the Aeroplane 



i6i 



to that of a person skating very rapidly over thin ice. If 
the skater were to stand still the ice would break, but he 
moves so rapidly that it does not have time to break. 
While this is a good illustration and may help us to under- 
stand why a light fluid substance like air is able to support 
in perfect security a very heavy machine, it must be re- 
membered that this is only an illustration and does not 
really explain. If an aeroplane is moving forward in a 
horizontal direction, the upward lifting force at any mo- 
ment or any successive number of moments must equal the 
weight of the machine or else it will constantly fall to a 
lower level and eventually reach the ground. 

The planes of an aeroplane are curved upward so as to 
enable them better to catch the wind and prevent the air 





Fig. 58 — Stream line construction. 

from escaping underneath so rapidly. This increases the 
lifting power from one-fourth to one-half. The stream line 
construction is adopted for all parts of frame and body. 
The effect of this is seen in Fig. 58. If any portion of the 
frame is square in cross-section, as it moves rapidly through 
the air a partial vacuum is created behind and the ''head'^ 
resistance becomes very great. If on the other hand it is 
somewhat oval in section and elongated with a sharp cut- 
ting edge, the air flows evenly from it and diminishes very 
much the resistance. 



l62 



The Boys^ Own Book oj Great Inventions 



Stability and Steering. — Stability is the most vital factor 
in successful aviation. In an aeroplane it is of two kinds, 
longitudinal, or endwise and lateral, or sidewise. By sta- 
bility we mean the ease or difficulty with which a body 
may be overturned. In an aeroplane this matter of sta- 
bility is intimately connected with two points, the center of 
pressure already explained and the center of gravity. The 
center of gravity is the point at which the weight of a body 
might be regarded as concentrated. If suspended at this 



r 
1 




----- 1^4 


1 






-1 






i 






I 






* 

1 

1 


— -^ 


1 

1 
1 




4K- — --- 


1 

■ 


_. 


■ 






'- -/4 - -i 



Fig. 59. 



point a body will always balance in whatever position it may 
be placed. Now in order to secure longitudinal stability it 
is necessary to keep the center of gravity and the center of 
pressure together or as nearly so as possible. 

To illustrate this point cut a piece of bristol board as 
shown in Fig. 59. Holding it by the small end in a horizontal 
position let it drop and you will find that it begins to tip 
and turn and will quite likely fall upside down. Now place 



The Principles of the Aeroplane 



163 



a number of paper clips along the front edge evenly spaced 
and holding it as before let it drop again. This time it will 
fall gracefully to the floor without any turning movement. 
The center of pressure is toward the front of the larger 
plane and by weighting the front edge we have brought 
the center of gravity to about the same point. 



% 



i^^--^ 



>p 



W 

Fig. 60. — Rel^ition of center of pressure and center of gravity to each other. 

Why these two points should be together will become 
clear from a consideration of Fig. 60. The line AB represents 
one of the main wings of an aeroplane and ab one of the 
horizontal tail planes. Now suppose the center of gravity 
of the big plane is at C and the center of pressure nearer the 
front edge at P. The effect of these two forces, the weight 
of the plane at C and the air pressure at P, is to revolve 
the whole plane around in the direction of the arrow. But 
if these two forces were acting at the same point this turn 
ing effect could not take place. 

It will be noted that this turning of the main plane also 
turns, the tail plane, producing a pressure at P' and just like 
a lever this opposes the rotation. Here, too, we see the 
great stablizing influence of the tail planes set far behind 



164 



The Boys' Own Book of Great Inventions 



the main planes. This tail plane is pivoted and by means 
of wires attached to it is under the control of the pilot who 
can adjust its inclination so as to make the pressure on it 
just enough to counteract this effect of rotation. By put- 
ting sufficient pressure on the tail plane, too, he can tilt the 



^ 
\ 


1 




\ 




\ 


\ 


1 
1 




\ 
\ 
\ 

\ 
\ 
\ 


1 
1 
1 
1. 




\ 
\ 


1 
1 
1 
1 
\\ 





VERTICAL TAIL plane: 



Fig. 61. 



main plane so as to bring the center of pressure back to the 
center of gravity. The position of the center of pressure 
depends upon the angle at which the plane strikes the wind. 
The smaller this angle the nearer the front edge of the plane 
it is. 

In ascending to a higher level the pilot tilts the horizontal 
tail plane so as to raise the front edge of the main plane. 



The Principles of the Aeroplane 



i6s 



This increases the pressure on the main plane and therefore 
the vertical component is increased sufficiently to lift the 
machine. In descending the process is reversed and to 
maintain flight in a horizontal direction this angle at which 
the plane meets the wind is made just enough to make the 




Fig. 62. — Device for warping the wings. 

vertical component of the pressure equal to the weight of 
the machine. 

A vertical tail plane under the control of the pilot and 
acting exactly like the horizontal plane steers the machine 
to left or right. This is shown in Fig. 61. 

The long planes placed crosswise of the machine tend to 
give lateral stabiHty but very frequently the pressure upon 
one wing will become greater than that on the other and if 
not equalized the machine will overturn. The most satis- 
factory device for accompUshing this is the Wright brothers' 



i66 The Boys^ Own Book of Great Inventions 

mechanism for warping the wings. A rough diagram of 
this mechanism is shown in Fig. 62. By warping down the 
wing on which the greater pressure occurs the effective lift- 
ing area will be diminished and the excessive pressure eased. 
At the same time the other wing is warped up which in- 
creases the pressure on this wing with the result that the 
pressure on the two wings is equalized and the machine 
righted. Both movements are performed by one operation 
and at the same time the rudder is turned just enough to 
keep the aeroplane on its course. Without such a device it 
would be impossible to make curves, for in flying in a circle 
the outer wing of the plane moves faster than the inner 
wing and therefore the pressure upon it is greater and must 
be neutralized by wing warping or the use of small auxiliary 
planes called ''ailerons." The use of the Sperry gyroscope 
stabilizer for this purpose has already been explained. 

Speed and the Size of the Planes. — Since, if we double the 
speed of our machine, we multiply the air pressure upon its 
wings by four it follows that with double the speed we may 
get the same lifting power with one-quarter the wing area. 
The early Wright machine had 500 square feet of wing 
surface and a speed of forty miles an hour. But at 80 miles 
an hour the necessary wing surface would have been only 
125 square feet and at 160 miles only 31J4 square feet. 
This shows why high speeds are desirable and accounts for 
the fact that with modern engines of large horsepower 
aeroplanes can be made so much smaller than formerly. Of 
especial value is this in military aviation. 

Experiments on Aeronautics 

Pressure of the Atmosphere. — Secure a tin can — a gallon 
alcohol can or turpentine can for example — having a smooth 



The Principles of the Aeroplane 167 

neck. Place a little water in the bottom and heat on the 
stove or over a gas burner until steam is issuing freely from 
the neck. Then while the water is still steaming briskly, 
stopper the neck tightly with a close fitting cork and im- 
mediately plunge beneath a cold water faucet or immerse 
in a tub of cold water. You will be surprised to see the 
unrecognizable shape into which your tin can will be 
crushed. The boiling water drove out the air replacing it 
with steam and when this was condensed by the cold water 
a vacuum was left and the atmospheric pressure outside 
did the rest. 

Buoyancy and Balloons. — Make a strong soap solution by 
rubbing castile soap in a basin of clean water. Add a few 
drops of glycerine and if the water is not cold allow it to 
cool. Now connect a clay pipe to a gas jet with a long piece 
of rubber tubing and blow bubbles as you used to do. Just 
before detaching the bubble turn off the gas and then de- 
tach it with a quick downward movement. If the bubble 
is large it will rise to the ceiling but with a little practice 
bubbles can be blown that will float in the air without 
either rising or falling. The bubble that rises weighs less 
than the volume of air that it displaces and rises just as a 
balloon does. The bubble that floats without rising has 
exactly the same density as the air. Again, smaller bubbles 
can be blown that will immediately settle to the floor and 
these represent the condition of the balloon when gas has 
been allowed to escape until it is heavier than the surround- 
ing air. 

A Simple Flier. — ^A toy flier suitable for demonstrating 
the principles of the aeroplane is illustrated in figure 63. It 
consists of a very Hght, straight-grained piece of wood to 
which are attached the planes and propeller. The stick 
should be about 9 inches long and the main plane 63^ 



i68 



The Boys' Own Book of Great Inventions 




'(t> 



Fig. 63. 

inches by 2 3/2 inches. The planes may be cut from cardboard 
iand the propeller also may be of the same material. Bristol 
board is excellent for this purpose. As shown in the figure 
the stick should carry a wire hook on the under side and end 
in a shoulder for mounting the propeller shaft. A small 
glass bead slipped over the shaft and coming between the 
shoulder and the propeller will serve for a washer. A 
twisted rubber band fastened to the hook on the propeller 
shaft and to the hook on the stick constitutes the motor. 

Experiments with this toy machine having planes of 
varying sizes and bent at different angles will afford both 
amusement and instruction in the principles of flying. 

A Sling-Shot Glider. — ^A ghder capable of making a sus- 
tained flight over a considerable distance and operated in 
the same manner as an ordinary sling-shot is shown in 
figure 64. A light straight-grained stick is provided 
at each end with elevating blocks. A hook is securely 
iastened to the forward end and a vertical keel beneath the 



The Principles of the Aeroplane 



169 




Fig. 64. 



rear plane. Planes cut from cardboard or very thin wood 
may be secured over the elevating blocks by means of 
rubber bands. Then attach a stout rubber band to an 
ordinary ''bean-shooter" crotch and shoot your gHder in 
the same manner as a sling-shot. Long and graceful flights 
may be obtained and by adjusting the inclination and 
position of the planes the glider may be made to perform 
many interesting evolutions. 

A Model Monoplane. — In figure 8 is shown the construc- 
tion of a fair-sized model flier. The frame consists of two 
sticks of spruce 36 inches long and }/i oi ^ii inch square 
separated at the rear by a stream line cross-brace 8 inches 
long and tapering to a point at the front. A second cross- 
brace should be placed about one-third the distance from 
the forward end. These braces may be securely wound to 
the side beams with silk thread and covered with glue and 
shellac. The forward ends of the side beams are cut at an 
angle and glued together. A piece of stout wire having 
hooks on each end is bent to fit the nose of the frame and 
secured in place with silk thread and glue. These hooks 



170 The Boys^ Own Book of Great Inventions 

will serve for attaching the rubber bands. Two fine guy 
wires are stretched diagonally between the cross-braces to 
give greater stability. 




Fig. 65. 

The rear plane is made by bending piano wire to shape 
over a wooden pattern and soldering the ends. This form 
should be 18 inches long and 43^ inches wide. Two cross- 
ribs bent so as to arch upward about a half inch from the 



The Principles of the Aeroplane 171 

horizontal are soldered to the main frame. This frame is 
then fastened to the side beams with silk and shellac and 
over it is stretched fine waterproof silk. This covering 
should be laced tight as a drum-head with silk thread. The 
forward plane should be 8 inches long, 2 inches wide 
and elevated so as to make the wings tip upward at an 
angle of about 10 degrees from the horizontal. A pine 
board about V25 of ^.n inch thick may be steamed and bent 
to shape. It may be secured to the side beams by a stout 
rubber band or fastened with silk and shellac. The front 
edge of this plane should be slightly raised by means of 
elevating blocks placed on the beams. 

The propeller blades should be about 83^ inches long, 
7i8 of an inch in thickness and made of hard wood. They 
may be cut in outline from a half-inch board and then 
carved to shape, but it will be more satisfactory to buy 
ready-made propellers from some dealer. The end of each 
side beam should carry a brass elbow having a small hole 
drilled in it for mounting the propeller shaft. A small 
steel washer must be slipped on the propeller shaft so that 
it will come between the hub of the propeller and the brass 
elbow. To reduce friction place vaseline between the mov- 
ing parts. Shafts much superior to the home-made type 
may be bought for a few cents. 

For each motor use 8 strands of J^ inch flat elastic and 
give them about 1,000 turns either by hand or with a me- 
chanical winder which may be obtained from any dealer. 

A Light- Weight Flier. — Select a stick of spruce or some 
other Hght wood 36 inches long and J^ inch square. The 
main plane should be 16 inches by 4 inches and the smaller 
one 9 inches by 2 inches. These should be cut from a board 
V16 of an inch thick and may be worked down with sand- 
paper somewhat thinner. Round off the comers. Then 



172 The Boys^ Own Book oi Great Inventions 

steam the planes and bend the wings upward slightly from 
the middle. Fasten the planes to the stick with rubber 
bands until balanced and adjusted and then glue them in 
place. Cut a propeller blade 6 inches by i inch from a half- 
inch board. Carve this to shape and make it as thin as 
possible. Mount the propeller as in the previous model and 
place a hook on the forward end of the stick. Use two or 
three strands of Vs inch rubber for the motor and fly your 
plane with the wind. 



Chapter X 
^'THE ASSASSIN OF THE SEA" 

The submarine, well called ''The Assassin of the Sea," 
is a marvelous product of the inventive genius of the race 
appHed to the evil business of war. A wholly untried factor 
at the beginning of the Great Struggle, its phenomenal 
development and unrestrained use in the hands of an un- 
scrupulous and desperate nation, has revolutionized his- 
toric methods of naval warfare. Unlike its counterpart of 
the air its sole purpose is destruction — destruction of life 
and property on a scale and with a degree of ruthlessness 
never before practiced by civilized people. The aeroplane 
and airship will be even more useful in the pursuits of peace 
than they have been destructive in time of war. But not 
so with the submarine whose crown of glory has been a 
felon's blow, her greatest achievement the spread of "fright- 
fulness. " 

Although left for other nations to develop, the sub- 
marine is an American invention. Just as every great in- 
vention is preceded by numerous crude attempts to ma- 
terialize the idea which it embodies so was the submarine. 
The first of these was by Van Drebble, a Dutchman, early 
in the seventeenth century. But one hundred and fifty 
years later David Bushnell, an American, made the first 
real submarine. This was during the War of Independence 
in 1776 and its only exploit was an unsuccessful attempt to 
sink the British man-of-war Eagle lying in New York Har- 
bor. This unique craft stood on end, carried a crew of one, 

173 



174 The Boys^ Own Book of Great Inventions 

was operated by man power and could remain submerged 
haK-an-hour. Just as in modern submarines, it was sub- 
merged by admitting water to the ballast tanks and was 
brought to the surface by pumping this water out. A lead 
keel of 200 pounds weight kept the boat in an upright 
position and could be quickly detached if an emergency 
should make necessary an immediate rising to the surface. 

The next man to interest himself in underwater craft 
was Robert Fulton, better known as the inventor of the 
steamboat. In the uncertain financial condition of this 
country during Washington's administration, Fulton de- 
cided to transfer his energies to France. There he succeeded 
in interesting Napoleon in the project and received financial 
aid for the construction of the Nautilus. In this he adopted 
the familiar cigar-shaped type and built a boat about 21 
feet long, covered with copper and operated Hke Bushnell's 
*' Turtle" by man power. With this he was able to remaiQ 
submerged for 5 hours and by admitting or pumping out 
water could sink or rise at will. Although he succeeded in 
attaching a bomb to a pontoon structure and blowing it to 
atoms, he had no opportunity to try his luck with a British 
warship and Napoleon refused to have anything further to 
do with the new craft. 

Fulton then went to England and was successful in in- 
teresting William Pitt, the prime minister, in his new boat. 
Before a commission appointed for the consideration of the 
matter Fulton gave a demonstration in which with a charge 
of 170 pounds of gunpowder, he blew up an old brig de- 
tailed for the purpose. His method was to submerge, and 
coming up under the unsuspecting craft fasten his torpedo 
to the hull which would be exploded by a clockwork timing 
device set to operate like an alarm clock at a certain definite 
time. The naval authorities and commission being un- 



" The Assassin of the Sea " 175 

friendly to this new weapon of war, Fulton returned to 
America and very reluctantly applied himself to the per- 
fection of a steamboat. He made a later but unsuccessful 
attempt to interest Congress and in the War of 181 2 one 
of his submarines made several attacks on a British man- 
of-war off New London. 

In the Civil War the Southern Confederacy made the 
first successful submarine attack upon an enemy ship 
during actual hostilities. This crude craft, called a 
*' David" because of its diminutive size in comparison with 
the "GoHaths" of the Northern navy, could hardly be 
called a submarine. It moved along the surface with its 
keel submerged, being able to dive for only a few minutes 
at a time. On the night of February 17, 1864, one of these 
little Davids carrying a crew of nine and a spar-shaped 
torpedo entered Charleston Harbor. Making straight for 
the Housatonic its torpedo struck the big ship in the vi- 
cinity of the magazine and the earthquake-like explosion 
sunk her in a few moments. The submarine and crew were 
also lost, and it is hardly possible they could have hoped to 
escape. 

After the Civil War nothing more was done until toward 
the end of the century. Mr. Thorsten Nordenfelt, a Swedish 
inventor, next made an unsuccessful attempt at submarine 
construction. The great obstacle in those days was the 
lack of satisfactory motive power, but this problem was 
solved by three of the most timely and important of modern 
inventions — the electric motor, the storage battery and the 
gasoline engine. Making use of the first two or these in- 
ventions Gustave Zede, a Frenchman, built two undersea 
craft, the latter of which was 160 feet long, 123^ feet wide, 
and had a displacement of 270 tons and carried 173^ inch 
Whitehead torpedoes. 



176 The Boys^ Own Book of Great Inventions 

The real initiative in modern submarine construction, 
however, was taken by two American inventors, Simon 
Lake and John P. Holland. These men originated and 
patented the two types which with modifications and im- 
provements are found to-day in every navy of the world. 
Just as the early work on the aeroplane was done in this 
country so was that on the submarine, but the purpose of 
the inventors was totally different from that of the outlaw 
nation into whose hands this new weapon has temporarily 
passed. 

The Lake Submarine. — ^Lake's purpose in building a sub- 
marine was the direct opposite of war. Realizing the large 
number of wrecked ships and valuable cargoes lying on the 
ocean bottom in comparatively shallow water, he con- 
ceived the idea of building vessels that should be able to 
move over the ocean bed and salvage this vast treasure. 
His first submarine, a very small affair, was built in 1894 
and christened Argonaut Junior. It was only 14 feet long, 
43^ feet deep and 5 feet wide, but it was equipped with 
wheels for moving over the ocean bed and through a com- 
partment in the bow a diver was able to step outside for 
salvage work. The depth limit was 20 feet. This first 
attempt proved a great success and Lake quickly followed 
it with two other boats each of which was equipped with a 
gasoline engine. These were very seaworthy craft and 
could weather the roughest sea. They carried an air supply 
sufficient for a continuous submergence of forty-eight hours 
and sleeping accommodations for the crew. 

The commercial possibiHties of the new craft not being 
realized, the inventor in 190 1 began the construction of a 
naval submarine. As in the previous types this vessel 
submerged on an even keel by admitting water to the bal- 
last tanks and rose again by pumping this out and admit- 



;/• 



* ' The A ssassin of the Sea " 177 

ting air in place of it. Although equipped with horizontal 
rudders, like an airship, these were not regularly used for 
descent and ascent. In rising the pumps must be able to 
develop a pressure equal to that of the water outside which 
at a depth of 100 feet is about 60 pounds per square inch. 
For quick rising in the case of an emergency these sub- 
marines carry a false keel of considerable weight which can 
be released by throwing a lever and this loss of ballast 
causes the vessel immediately to rise. For nmning on the 
surface, which is the true sphere of action except when 
safety demands submergence, gasoline engines were used. 
When submerged it is of course impossible to nm such an 
engine because of the insufficient supply of air and there- 
fore electric motors were employed. These were operated 
from storage batteries and the storage batteries were in 
turn charged from a dynamo run by the gasoline engine 
when the submarine came to the surface. 

These were the essential features of the Lake submarine 
as they still are of all such under sea boats. This first sub- 
marine was able to make a speed of only 8.5 knots on the 
surface and 5.4 knots when submerged. The United States 
being unwilling to purchase the craft, it was sold to the 
Russian Government and proceeded to Vladivostok. 

It may be well at this point to give a brief explanation of 
how a submarine changes its depth. All submarines are 
built to nm on the surface and because of greater fuel econ- 
omy and the higher speeds there attainable this is always 
done except where safety demands submergence. But sub- 
mergence to any considerable depths can be effected in 
from two to three minutes. Now any body floating or 
submerged in a liquid is buoyed up by a certain force. We 
are all famihar with the fact that it is easier to lift a stone 
when it is under water than when in the open air. We 



178 The Boys^ Own Book of Great Inventions 

know, too, how much heavier a bucket of water gradually 
grows as we lift it from the water. A block of wood or any 
other floating body is evidently buoyed up by a force equal 
to its own weight. Now the amount of this buoyancy is 
equal to the weight of the Hquid displaced whether the 
body sinks or floats. A cubic foot of water weighs 623/2 
pounds and therefore a cubic foot of rock when submerged 
in water will weigh 623^ pounds less than it weighs in the 
air. If a body floats it must be lighter than the water in 
which it is placed, i. e., a cubic foot of it must weigh less than 
62}/^ pounds. If the body weighs more than this per cubic 
foot it will sink. If it weighs less, in order to sink it must 
displace more than its own weight of water and this is im- 
possible unless it be held down by some additional weight. 
If a body weighs just 62^^ pounds per cubic foot, then its 
density is exactly the same as that of water and it will stay 
at any depth it may be put. The material in a battle ship, 
if put into one soHd mass, would weigh much more than an 
equal volume of water and therefore would sink, but when 
arranged in the form of a ship we must consider its average 
weight per cubic foot and this is more than half air. There- 
fore its average density is much less than that of water. 
Now when a submarine is floating on the surface of the 
sea it must be that its density, or weight per cubic foot, is 
less than that of water. Likewise when it submerges it 
must have increased its density to more than that of water. 
In the Lake type of submarine this is exactly what happens 
and in all types the density is increased to practically that 
amount. For this purpose the submarine is provided with 
large ballast tanks. When on the surface these are empty, 
but at the command to submerge large valves in the bottom 
are opened and a rapid inrush of water quickly fills the 
tanks, driving the air out through valves in the top. The 



' * The A ssassin of the Sea " 179 

capacity of these tanks is such that when they are filled the 
average density of the submarine is just a very little less 
than that of the outside water. This water ballast is so 
distributed, too, that the vessel will not pitch but will 
settle on an even keel. To fill these tanks in a modern 
submarine requires but little more than a minute. Then 
with the engines running and the horizontal rudder planes 
slightly depressed the bow will incline downward from 2 to 
5 degrees and the vessel will gently gUde to any desired 
depth. Being of practically the same density as the outside 
water, it requires but very Httle rudder to keep the vessel 
at any required depth or to rise or descend at will. 

Submarines are built for maximun depths of from 200 to 
300 feet, but they seldom operate at depths of more than 
60 or 70 feet and frequently less. The depth to which a 
submarine may go depends solely upon the strength of its 
walls, i. e., its ability to withstand the outside water pressure. 
At a depth of 300 feet this is about 150 pounds per square 
inch. The pressure inside the submarine is of course but 
one atmosphere, or the same as that of the air at the surface 
— 15 poimds per square inch. 

In a vessel of the Lake type which does not avail itself of 
horizontal rudders for descending and ascending the dens- 
ity of the submarine must be made greater than that of the 
water to sink and less to rise. In the latter case the pumps, 
driven by compressed air, are required to develop a pressure 
equal to that of the outside water, for the water must be 
pumped out before the vessel can rise. In most modern 
types the water is admitted and pumped out at the surface 
and descent and ascent made by the action of a horizontal 
rudder in just the same way that an air ship rises and falls. 
The lightening of a submarine by the discharge of a tor- 
pedo suddenly increases its buoyancy and the tendency 



i8o The Boys^ Own Book of Great Inventions 

to rise must be immediately balanced by taking in more 
water. 

A swimming fish is a natural submarine. By means of 
an air bladder he increases or decreases his density at will 
and by the use of fins corresponding to the rudders of a 
submarine he glides whither he will. 

The Holland Submarine. — ^John P. Holland, an Irish 
American, is the real inventor of the present type of sub- 
marine. The shape of Lake's vessel was very much like 
that of an ordinary ship and it carried an upper deck of 
considerable extent. The Holland submarine was of the 
typical spindle form with very Httle superstructure and 
designed entirely for war purposes. Holland built his first 
boat in 1898. Compared with present day craft it was a 
miniature affair having a displacement of only 70 tons and 
making but 5 knots when submerged. This little vessel, 
however, attracted world-wide attention and was given 
the severest tests both by our own government and by the 
representatives of other powers. It began to be realized 
that the day of the submarine had come and it is worthy 
of note that the submarine and aeroplane came together. 
These two great weapons of modem warfare are products 
of American invention, though foreign nations have con- 
tributed very largely to their development and appHcation. 

England purchased outright the Holland patents for use 
in her navy and began the improvement and development 
of the new type into a very formidable instrument of naval 
warfare. Our own government, too, adopted this type and 
although not keeping pace with submarine development 
in several of the foreign navies, yet has done much pioneer 
work. The only first class power that seemed to regard the 
submarine as an experiment of doubtful value was Germany. 
She waited for developments in other navies and then 



The Assassin of the Sea '* 



i8i 



established her own works under the direction of the Krupps 
and proceeded to evolve the Germania or modern U-boat, 
which is a development from an original French type. At 
the outbreak of the Great War she was still a third class 
power in submarine construction and only when Great 
Britian entered the ranks of her enemies did she turn to the 
development of the submarine in earnest. The submarines 
built prior to this time were mostly for coast and harbor 
defense, having a displacement of 500 tons or less and a 
cruising radius of less than a thousand miles. 

Construction and Equipment. — The construction of a 
submarine is well shown in the accompanying cuts. The 




INNtRHULL 

By courtesy of Scientific American. 

Fig. 66. — Construction of a submarine. 

hull in some navies is single and in others double. Water 
ballast is placed both fore and aft and so distributed as to 
give longitudinal stabihty. Provision is made for increas- 
ing the amount of ballast in exact proportion to the con- 
sumption of fuel oil and the loss of weight from torpedo 
fire. For blowing out these compartments and also for the 
discharge of torpedoes there are large compression tanks 
containing air at a pressure of 2,500 poimds per square inch. 



1 82 The Boys^ Own Book of Great Inventions 

The feature which first attracts one's attention on the 
deck of a submarine is the conning tower, sometimes called 
the ^* brain" of the vessel. When sailing on the surface its 
roof serves as the navigating bridge and within it are con- 
centrated the signal and control devices by which the sub- 
marine is operated. Here we find the periscope, the wonder- 
ful *'eye" of the submarine, a repeater from the master 
gyro-compass below, a number of recording instruments 
and telegraphs for signaling to different parts of the vessel. 
Through ports just above the deck line observation may be 
made in any direction when travehng ''awash," i. e., with the 
surface of the sea just on a level with the deck. 

The most vital part of a submarine's equipment is the 
power plant, for upon the capacity and efi&ciency of this 
depend its speed and cruising radius. This has been and 
is to-day the most troublesome problem in submarine con- 
struction and operation. The gasoline engine, electric 
motor and storage battery seemed to offer a solution and 
while their use has made possible the modern submarine 
they possess drawbacks. 

Because of the insuJB&cient supply of air and the impos- 
sibility of exhausting the cylinder gases against high water 
pressures, it is impossible to use the gasoline engine except 
for surface running. Therefore storage batteries and elec- 
tric motors were adopted for submerged traveling. These 
storage batteries can never be used for more than 20 to 25 
hours without recharging, and when running at the maxi- 
mum speed of 1 1 to 1 2 knots they may be exhausted in one 
hour. Therefore at least once in every 24 hours the sub- 
marine must come to the surface and recharge its batteries. 
This is done by running one of the electric motors back- 
wards as a dynamo by coupling it to the gasoline engine 
and passing the current into the batteries. This can be 



" The Assassin of the Sea " 183 

done at the same time that the submarine is cruising on the 
surface and in spite of the name this is the normal way for 
a submarine to travel. 

For use in confined space a highly inflammable and volatile 
liquid fuel like gasoline has been found extremely dangerous. 
It is practically impossible to prevent its evaporation and 
escape into the air of the submarine where if present in 
sufiicient quantity a spark from the electric motors will 
ignite it. Gasoline, too, requires high speed engines, is 
expensive and is consumed at a very rapid rate, thus 
shortening the cruising radius. 

But all these difficulties disappeared with the invention 
of the Diesel oil engine. This is a low speed engine using 
heavier and cheaper oils such as kerosene and benzol and 
requires no carburetor or spark coil. On the up stroke of 
the piston the cylinder is full of air which is compressed to 
500 pounds per square inch. This compression generates 
enough heat to ignite the oil which is sprayed into the 
cylinder at the top of the stroke. The combustion which 
follows generates a large volume of gases and raises their 
temperature to about 3,000 degrees Fahrenheit, shooting 
the piston downward. An inflow of fresh air immediately 
follows the escaping exhaust gases, which is compressed on 
the upstroke and the operation is repeated. Thus this is a 
two-cycle engine. With this engine the power output 
is higher, the fuel economy much greater and there is 
no danger from explosion of escaping gasoline. The Diesel 
engine is now used on all undersea craft and is one of the 
greatest inventions of recent years. 

For submerged traveling nothing has taken the place of 
storage batteries and electric motors. One element of 
danger from the storage battery is the possible leakage of 
salt water into the cells, which reacts with the sulphiuic 



184 The Boys^ Own Book of Great Inventions 

acid and lead oxides to form the poisonous gas chlorine. 
This happened with the United States submarine E2 during 
the autumn of 19 14. The storage batteries are also used 
for electric hghting, for the operation of the ventilating 
system and the running of the motors which control the 
steering gear. 

The periscope is absolutely essential to the stealthy ap- 
proach, the fatal aim and the quick get-a-way of this ser- 
pent of the seas. Without it the submarine, except when 
cruising awash, would be as blind as a bat. Although the 
periscope in crude form dates from 1864, its wonderful 
perfection has been accompKshed during the last ten years. 
The diagram in Fig. 67, shows the essential features of this 
instrument. The rays of Hght from a distant object pass 
through the objective O and entering the total reflecting 
prism R are reflected at right angles straight downward 
through a system of lenses to another total reflecting prism 
where the rays are again reflected at right angles into the 
lenses of the observing telescope. The lens system in the 
tube is for slight magnification, the reinversion of the image 
and the correction of distortion. Such a periscope gives a 
range of about 60 degrees in whatever direction it may point 
and can be rotated through the whole circle of 360 degrees. 

It is of course highly desirable to be able to command the 
whole horizon in one view and for this purpose a periscope 
with a circular lens for objective has been perfected. This 
is one of the greatest optical triumphs ever made and has 
been carried out by English and German opticians working 
independently of each other. In this periscope there are no 
less than seventeen sets of lenses to overcome what at 
first seemed insuperable obstacles of distortion, aberra- 
tion, etc. The periscope gives a circular field of view in- 
cluding the whole horizon but with a dark spot in the center. 



^^The Assassin of the Sea'' 



185 



R -- 




obseirvation 
teilelscope: 



^^miiii2> 




^^rTTTTTTr^ 



•R] 



Fig. 67. — A periscope. 



1 86 The Boys^ Own Book of Great Inventions 

To fill this space a direct vision periscope is provided so 
that in the center is obtained an image of the scene directly 
ahead of the submarine while about it is a fringe showing 
clearly every point of the compass. It is possible to throw 
these images on to a ground glass screen placed beneath the 
periscope, but this is practicable only in very clear weather 
and never when exact details are essential. 

With the periscope projecting 20 feet above the water a 
battleship may be picked up at a distance of about 6 miles 
in clear weather. With the periscope 3 feet above the water 
the range is restricted to about 2 miles and at i foot to barely 
a mile. At night the periscope is of no value unless the moon 
is shining brightly and even then its use is very limited. 
Even when the periscope is shot away water cannot enter 
the submarine and by means of compass and conning tower 
escape is assured. 

The Torpedo, the most deadly projectile of modern war- 
fare, is really a self-propelled submarine in itself. The 
famous Whitehead torpedo was invented and brought to 
perfection by a British engineer residing in Austria about 
the year 1876. As originally perfected this torpedo car- 
ried about 26 pounds of gun-cotton and had a speed of 
18 knots. Present day torpedoes are from 18 to 21 inches 
in diameter and about 20 feet long. They carry from 175 
to 300 pounds of gun-cotton and have a speed of from 30 to 
45 knots. The maximion range is about 634 miles. 

The shell of a torpedo is made of tough vanadium steel 
of about a haK inch in thickness. The head is filled with 
the charge of gun-cotton and extending directly through 
the explosive mass is a steel rod called the "pistol." The 
inner end is pointed and rests directly against the detonator 
which lies behind the gun-cotton. The part projecting 
beyond the nose of the torpedo is threaded and fitted with 



*' The Assassin of the Sea " 187 

a small propeller. As the torpedo is discharged and passes 
through the water this propeller begins to revolve and un- 
screws itself from the rod, dropping off at a distance of 150 
feet from the submarine. This prevents the premature 
discharge of the torpedo by coming in contact with any 
obstacle within the safety zone of the submarine itself. 
Following the charge of explosive is an air chamber con- 
taining compressed air under a pressure of 2,150 pounds 
per square inch to operate the small four-cylinder engine 
for propelKng the missile through the water. The engine 
and gyroscope-steering device are in the stern section. Two 
propellers immediately behind rotate in opposite directions. 
A small alcohol burner contained in the middle section is 
ignited just as the torpedo is fired, and by preheating the 
air before it enters the engine the distance to which the 
torpedo can be fired is increased to a remarkable extent. 

The torpedo tubes are in the bow and stern of the vessel. 
In loading, their breech locks are thrown open and the 
torpedo sHd into position by machinery. The breech locks 
are then closed and the ofiicer on duty in the conning tower, 
having taken the range of his target and set the mechanism 
for the proper depth and angle, presses an electric button 
and the deadly missile speeds on its way. The torpedo is 
discharged by compressed air and just as the discharge 
takes place a small conical-shaped cap fitting over the tor- 
pedo tube swings open. Immediately after the torpedo 
has passed this cap closes to prevent the entrance of water, 
but in a compensating tube above, just enough water is 
automatically taken in to make up for the weight of the 
discharged torpedo. Contrary to the common idea the 
torpedo does not travel on the surface but at a consider- 
able depth, depending on whether the target is a large ship 
or a small destroyer. The best means of detecting its ap- 



1 88 The Boys^ Oimi Book of Great Inventions 

proach is by observation of the long trail of bubbles which 
come from the exhaust of the engine, but the torpedo will 
always be about loo yards in advance of these. The nose 
of the torpedo is provided with net cutters which enable 
it to hack its way, with Httle loss of velocity, through steel 
nets placed about a ship. When the torpedo strikes the 
ship's hull the pistol is driven backwards into the priming 
charge and the gun-cotton is fired. No ship afloat is able 
to withstand the terrific violence of such an explosion when 
struck fairly and squarely. 

The largest submarines to-day have a displacement of 
i,ooo tons. There may be a few larger than these but noth- 
ing definite is known of them. The maximum cruisiug 
radius is from 6,000 to 8,000 miles, and this is possible only 
at surface speeds of 11 to 12 knots. With the maximum 
speed of 18 to 20 knots the cruising radius would be re- 
duced to 1,000 miles. That these ocean-going submarines 
can cross the Atlantic has been demonstrated by the voy- 
ages of the Deutschland, the U53 and the submarines that 
preyed upon American shipping off our eastern ports dur- 
ing the spring of 1918. Convoyed by huge mother ships 
to supply them with fuel and lubricating oils, there appears 
to be no reason why a flotiQa of ocean cruisers could not 
cross the Atlantic and, establishing a base in the shallow 
coastal waters, lie in wait for American shipping at our 
very doors. So far it has been more profitable for Germany 
to attack commerce carriers on her own side of the water, 
and undoubtedly her supply of submarines has been limited 
and is quite likely growing smaller. 

There appears to be no one sure antidote for the submar- 
ine. The means of combating it are varied. One method 
which has accompHshed something but not much in the 
present war is to attack the submarine bases. This would 



^^ The Assassin of the Sea^^ 189 

be the surest and most effectual method and it is not at 
all improbable that v^dth an overwhelming superiority in 
the number of bombing planes possessed by the Allies this 
could be accomplished. Another method is to protect 
ships by sealing up the entrance to harbors and building 
ships of higher speeds than are possible with the submarine. 
The best method has been to hunt out and destroy the sub- 
marine wherever it could be found. For this purpose the 
torpedo boat destroyer has been found very effective. 
Having a speed practically double that of the submarine, 
this Hght craft has been able to run down and destroy by 
gun fire or ramming very many of the undersea boats. 
When convoyed by destroyers, battleships and transports 
are safe from submarine attack and this accounts for the 
great success of the Allies in ferrying troops during the 
Great War. Mines probably account for few submarines, 
and nets stretched across harbors and channels only afford 
protection for the shipping within. The aeroplane and 
airship when looking straight down into clear water and 
with cloudless skies are able to spot submarines, but the 
possibility of dropping bombs from a moving aeroplane 
upon a moving submarine is very uncertain. With the 
immense amoimt of Allied and neutral shipping entering 
and leaving the ports of Western Europe every day since 
this war began, it is most remarkable that more of it has 
not been sent to the bottom. 

For centuries to come this black night of submarine 
frightfulness culminating in the cowardly crime of the 
Lusitania and a thousand more will brand as outlaws and 
assassins the government that conceived it and the people 
who approved it. 

That the submarine will continue to increase its ef- 
ficiency and sphere of action there is little doubt. If an 



iQO The Boys^ Own Book of Great Inventions 

unscrupulous nation of organized assassins armed to the 
teeth with submarines and aircraft shall ever again make a 
surprise attack on the peace of the world, there will be no 
limit to the conquest that she may make. 

EXPERIMENTS ON TEE SUBMARINE 

The Cartesian Diver. — A very simple contrivance for 
showing the law of buoyancy as applied to submarines is the 
Cartesian Diver. Secure a glass cylinder similar to the one 
; 5i_-_-_-_^ shown in the cut. Fill it with water and sub- 
merge in it mouth down a small pill bottle. 
The bottle should contain water sufficient to 
make it just float. Then tie over the top of the 
cylinder a tightly stretched piece of rubber 
dam to confine the water. Place the palm of 
the hand on the top of the cylinder and press 
down gently. The pill bottle will immediately 
begin to descend and will sink to the bottom. 
Upon releasing the pressure it will rise to the 
surface or by adjusting the pressure nicely the 
^^* * diver may be held at any desired depth. 
Upon careful observation it will be seen that, as pressure 
is applied to the surface above, the water rises in the bottle 
slightly, thus increasing its density to more than that of the 
water and causing it to sink just as a submarine does when 
it takes on ballast. As the pressure is relieved this water 
escapes and the increased buoyancy brings it to the surface. 
This experiment may be varied by substituting a large 
bottle with flat sides for the cyKnder. Insert the pill 
bottle and adjust it to almost the density of water. Then 
cork the bigger bottle tight and it will be found that the 
diver may be operated by simply compressing the two flat 
sides of the bottle with the hand. 




^^The Assassin of the Sea'' 191 

Flotation. — Secure a tall cylinder and fill it half full of 
a strong solution of common table salt. Very carefully 
pour down the side fresh water until the cylinder is full. 
Now drop into the cylinder an egg. It will settle until it 
reaches the layer of brine and there it will float. The egg 
has a greater density than the fresh water but is lighter than 
the salt water. 

Two Liquids of Equal Densities. — Olive oil does not mix 
with water and being Kghter floats on its surface. Fill a 
small tumbler half full of water and pour into it a little 
olive oil. Now add alcohol a little at a time with constant 
stirring and very soon the oil will collect in large spherical 
globules beneath the surface. These globules will remain 
suspended at any depth because the density of the alcohol 
and water mixture has been made equal to their own. 

Buoyancy. — Secure some regular solid, heavier than 
water, as a cement block. Take its dimensions and cal- 
culate its cubical contents as a fractional part of a cubic 
foot. Now with a spring balance weigh the block in air 
and then in water. Subtract the weight in water from the 
weight in air and find what fractional part of 62}^ pounds 
this loss of weight in water is. This fraction should be the 
same as the previous one representing the fractional part 
of a cubic foot occupied by the block. Why? 

Construction of a Periscope. — ^A very simple device for 
illustrating the principle of the periscope and one which 
will have considerable magnifying power can be made in 
accordance with the illustration in the accompanying figure. 

The objective O is a double convex lens of 14 inches focus 
and 1 3^2 inches diameter. The distance from the center of 
the lens to the center of the mirror M must be 3 inches. 
M is i3^ inches wide and long enough to fit the containing 
tube. Mirrors M and M' must be exactly parallel with 



192 The Boys' Own Book of Great Inventions 

M 




Mi — - 



Fig. 69. 



''The Assassin of the Sea'^ 193 

each other and at an angle of 45 degrees with the vertical. 
The distance between them is 1 1 inches. The eye-piece is a 
double convex lens of 4 inches focus and iVs inches diameter. 
The distance between its center and the center of the mirror 
is 4 inches. Thin strips of board may be cut of proper size 
and fitted together for the mounting of the lenses and mir- 
rors. Provision should be made for very slight adjustment 
of the eye-piece. 

The hght from a distant object passes through the ob- 
jective to the mirror M and is reflected to a focus on mirror 
M' from which it is again reflected through the eye-piece. 
In principle this is simply a telescope with mirrors added to 
change the direction of sight. The image will be inverted. 



Chapter XI 

THE STORY OF THE STEAM AGE 

Written all over the pages of history and interwoven 
in the fabric of human experience is the drudgery of man- 
kind. By pitifully slow and laborious processes the man- 
power of the race was for ages harnessed to the performance 
of its tasks. The pyramids of Egypt are colossal monu; 
ments to the infinitude of human toil. Surrounded by un- 
seen forces and great laws of Nature, especially calculated 
to assist them in the struggle for existence, men in their 
supreme ignorance plodded on without their aid. Slowly 
and painfully, as men groping in the dark, someone would 
discover a new principle, invent some crude mechanism or 
adapt some natural force to the performance of the world's 
work. Doubtless by accident the fundamental laws of 
machines were discovered and put into practical applica- 
tion in climasy, inefficient devices. Gradually the kinetic 
energy of moving air and running water was set to turning 
the wheels of industry and driving the ships across the sea. 
But up until the beginning of the last century the record 
of hiunan achievement had been very largely one of re- 
ligious, political and intellectual development. The world 
was still primitive. Mountains were insuperable barriers 
to trade and social intercourse. Oceans were crossed only 
by tedious voyages in almost miniature sailing vessels. 
In point of time the world was of immense proportions. 
The later labor saving devices that have multiplied the 
manpower of the race by thousands and even millions were 

194 



The Story of the Steam Age 195 

all unknown. The great divisions of labor and the conse- 
quent organization of industry were not even dreams. * ' The 
coach-and-four " was the fastest means of land convey- 
ance. People lived within themselves. Ideas traveled 
slowly. Superstitions still beclouded the minds of men. 
And then at the close of the eighteenth century came 
James Watt and the steam engine. Not Napoleon and the 
French Revolution but Watt and the inauguration of the 
Steam Age with its tremendous industrial revolution are 
the more important epoch-making events of those mo- 
mentous times. More than the growth of political ideas 
the application of steam power in the workshops of the 
world struck the shackles from the toilers of the race and 
gave them time to Kve. 

It is safe to say that no other invention can be compared 
with the steam engine in its influence upon the marvelous 
industrial and material progress of the last century. Its 
coming marked a turning point in civiHzation. But al- 
though we have referred to Watt as its inventor, the idea 
of a steam engine was not original with him. He is rather 
the genius who taking the ideas of the past and the crude 
imperfect devices of previous workers, fashioned them 
into a practical mechanism so far in advance of anything 
before produced that all the world has unhesitatingly ac- 
corded him full credit for the invention. It is true, too, 
that Watt did invent and perfect the modern steam engine. 

Like many other great inventions the steam engine had 
its origin in a long period of previous experimentation. 
Without going into the details of this early history we shall 
take up briefly the Newcomen engine, the immediate an- 
cestor of Watt's invention. Thomas Newcomen was a 
blacksmith, of Dartmouth, England, who in 1705 invented 
a mechanism for pumping water by the aid of steam. The 



196 



The Boys^ Own Book of Great Imentions 



device by which he did this is shown in Fig. 70. Steam from 
the boiler B was admitted to the cyHnder C by opening 
valve V where it Kfted the piston. Valve V was then 
closed and water admitted to the cylinder from tank T 




Fig. 70. — The Newcomen engine. 

by opening valve V. This jet of cold water condensed the 
steam, making a vacuum in the cyHnder, and the air pres- 
sure acting upon the upper surface of the piston forced it 
back down. The water was drawn from the cylinder 
through valve V". It will be seen that this was more an 
atmospheric engine than it was a steam engine in any 



The Story of the Steam Age 197 

modern sense. The piston motion was transmitted on 
through a walking beam FD to a pump rod and made to 
lift water from mines. It was a very slow and inefficient 
mechanism at best. The valves at first were operated by 
hand, but the story is told that a boy named Potter, who 
had been set to turn these valves, devised a system of cords 
in an ingenious fashion so as to make the walking beam do 
the work for him. In any case their action was soon made 
automatic. 

The most serious defect in the Newcomen engine was the 
great waste of fuel. After each movement of the piston the 
cylinder was cooled off by the cold water admitted and a 
considerable portion of the fresh steam was condensed each 
time before the piston could be raised. But still engines of 
this type were used for half a century and more to pump 
water and raise coal from mines and they represented the 
greatest achievement up to that time in the production of 
power-driven machinery. Because, too, of the great in- 
vention to which it led the Newcomen engine will always 
have an honored place in the history of steam power. 

James Watt, who overcame the defects of the Newco- 
men engine and developed it into a real steam engine, was a 
Scotch instrument maker at the University of Glasgow. 
One day in 1765 there was brought to him for repair a 
model of the Newcomen engine. The great waste of energy 
in the alternate cooHng and heating of the cylinder was at 
once apparent to Watt and he set himself to remedy this 
defect. After considerable experimenting, he hit upon the 
idea of exhausting the steam into a separate cylinder for 
condensation. He little dreamed at the time of the tre- 
mendous results that would flow from this brilHant idea. 
But he immediately put it into effect and the product of 
his first efforts is shown in Fig. 7 1 . The action was the same 



198 



The Boys' Own Book of Great Inventions 



as before except that the steam was forced by the down 
coming piston into a separate cylinder in which a jet of 
water maintained a partial vacuum. The engine still em- 
ployed atmospheric pressure and was single acting, but 




Fig. 71. — Watt's improved Newcomen engine. 

the steam was exhausted into a condenser as in modem 
engines and the great waste of energy was eliminated by 
keeping the main cylinder constantly hot. To assist in 
this he insulated the cylinder with wool. 

Watt's next great step was to transform his engine from 
an atmospheric one into a 100 per cent steam engine. He 



The Story of the Steam Age 



199 



did this by closing the cylinder to the atmosphere and ad- 
mitting steam, first on one side of the piston and then on 
the other. As the steam was admitted on one side, the 
exhaust valve on the other side was opened and the steam 
forced into the condensing chamber. To further utilize 
the energy of the steam Watt cut off the intake of steam 
each time before the end of the stroke and thus enabled it 
to expand against the piston. By thus being made to ex- 




FiG. 72. — Watt's governor. 

pand the steam was cooled and gave up a larger proportion 
of its energy. In other words, it was made to do more work. 
Two other improvements must also be attributed to 
Watt. One is the crank and flywheel for converting the to 
and fro motion of the piston into rotary motion. The 
other is the governor for controlHng the speed of the engine 
and keeping it constant. The former did away with the 
walking beam and connected the piston directly to the 
shaft which it was to turn. The connecting rod and crank 



200 The Boys^ Own Book of Great Inventions 

for accomplishing this, although devised by Watt, were 
first patented by James Pickard in 1780. The governor 
shown in Fig. 72 is operated by a belt passing from a small 
pulley on the crank shaft to another pulley at the foot of 
the governor. As the engine speeds up, the centrifugal force 
developed hurls outward the heavy governor balls. This 
allows the pivoted lever arm AB to rise, which acting 
through another lever on the valve in the steam pipe par- 
tially shuts off the steam and slows down the engine. On 
the other hand, a sudden increase in the load tending to 
diminish the speed of the engine weakens the centrifugal 
force and the governor balls moving in push the lever arm 
downward and the valve in the steam pipe opens wider, 
thus admitting more steam to the cylinder. In this way 
the speed of the engine is automatically kept constant. 
Although vast improvements in the details of construc- 
tion have been made since the time of Watt only two new 
principles have been utilized in the manufacture of re- 
ciprocating steam engines. These are superheated high 
pressure steam and the compound engine. By high pres- 
sure steam is meant steam that has been heated much 
above the boiling point of water by allowing the steam to 
accumulate in the boiler and thereby subjecting it to pres- 
sure. If water is heated in an open vessel at normal at- 
mospheric pressure it will boil at 100° C. If, however, the 
steam is confined pressure is exerted on the surface of the 
water and the temperature of both the boiling water and 
the steam rise. This simply means that more of the heat 
energy from the fire below is being stored up in the rapidly 
moving molecules of the water and steam. The greater the 
pressure of the steam the greater will be its temperature 
and the more energy it wiU possess. Now by building 
strong boilers and adjusting the safety valve so that the 



The Story of the Steam Age 201 

pressure and the temperature of the stearn will be high, we 
increase many times the quantity of energy that is trans- 
mitted to the cylinder and piston of an engine. Then by 
cutting off the inflow of steam while the piston still has 
about half of its stroke to make, the confined steam is made 
to expand to a larger volume and lower pressure, thereby 
transforming into the motion of the piston a larger propor- 
tion of the kinetic energy which has been stored up in it. 
At the same time this expanding steam does not cool enough 
to cause it to condense in the cylinder as it formerly did in 
the low pressure engines. All the heat given up by con- 
densation of steam to water was lost. Of course with high 
pressure steam the temperature falls as the steam expands 
and if it did not, no energy would be transformed into mo- 
tion, but the steam is not cooled sufficiently to cause con- 
densation in the cylinder. 

It was early recognized that a tremendous waste of energy 
was being suffered in the still very hot steam exhausted 
from the cylinder of an engine. It has come to be axiomatic 
now that heat is energy and energy is money. A method 
of diminishing this loss occurred to Jonathan Homblower, 
a contemporary of Watt, and in 187 1 he patented a com- 
pound engine. This principle was improved and is now 
utilized in all high class reciprocating engines. A compound 
engine is one emplo}dng two or more cylinders, each succeed- 
ing cylinder being of a larger diameter than the one that 
precedes it. As the steam expands in the first cylinder at 
a pressure of 200 pounds per square inch say, its volume 
increases and its pressure faUs to 100 pounds, perhaps. 
Now this steam which is still capable of exerting a high 
pressure is not condensed as formerly, but is passed into a 
second cylinder of twice the size of the first and made to 
expand again and drive another piston. Here its pressure 



202 The Boys^ Own Book of Great Inventions 

again falls to perhaps 50 pounds and it is passed into a still 
larger cylinder and made to do more work. Sometimes a 
fourth cylinder is added, but whatever the nimiber, the 
steam is exhausted from the last into the condenser where 
a high degree of vacuum is maintained. 

Thus high pressure steam and the compound engine 
have succeeded in utilizing a far larger proportion of the 
latent energy in fuel. But the best quadruple expan- 
sion and condensing engines are not more than 20 per 
cent efficient and the ordiaary locomotive is only 8 per 
cent efficient. In other words, in the locomotive 92 per 
cent of the energy in the fuel is wasted. When we consider, 
too, that of the billion tons of coal mined annually through- 
out the world, half of it is burned in the furnaces of steam 
boilers we see what an enormous waste there is, even in the 
best of mechanical devices. 

The action of the steam engine will become clear from a 
consideration of Fig. 73. The steam enters the steam chest 
and passing into the cylinder through the right hand steam 
port drives the piston to the left and the waste steam on the 
opposite side of the piston is forced underneath the slide 
valve and through the exhaust pipe into the condenser. 
As the piston continues to move to the left the slide valve 
at the same time moves to the right, closing the right steam 
port and allowing the confined steam to expand and do its 
work. When the piston has reached the end of its stroke 
the slide valve has uncovered the left steam port and the 
inrushing steam drives the piston to the right and forces 
the waste steam under the sHde valve and into the exhaust. 
The to and fro motion of the slide valve is produced by 
means of the eccentric. The eccentric consists of a disk 
placed on the shaft so that it is off center. Around this 
disk is bolted two straps connected with the eccentric rod 



The Story of the Steam Age 



203 



and in which the disk revolves. Then as the shaft and 
eccentric disk revolve a to and fro motion is given to the 
eccentric rod and slide valve. This is so set as to make the 




J--STEAM PIPE 




I FLY WHEEL.' | 



ECCENTRIC ROD, 



1~ , ECCENTRIC SXRAP^nn 
:^LIDB VALVE , 1—1 




ECCENTRIC ROD— t 



SHAFT 



ECCCNTRiC — 



Fig. 73. — The construction of the steam engine. 

slide valve uncover the steam ports for the supply and ex- 
haust of steam at the proper times. 

The immediate need of England at the time Newcomen 
and Watt made their great inventions was for an increased 
production of coal. The shallow mines had become ex- 
hausted and the man power and horse power of the industry 
were inadequate to raise the coal rapidly enough from the 
deeper mines to meet the increasing demands for fuel. 
Therefore the first task assigned to these new recruits in 
the ranks of industry was to pump water and lift coal from 



204 The Boys^ Own Book of Great Inventions 

the mines of the kingdom. By the beginning of the last 
century they had also been set to running the machinery 
in all sorts of mills and doing much of the work formerly 
done by wind and water. That tremendous expansion of 
industry characteristic of the Age of Steam, an age in 
which we still live, was just begun. 

The First Steamboat. — One of the first effects of this new 
found power was to stimulate a widespread interest in ap- 
plying it to improved means of travel and transportation. 
As was natural these first efforts were directed toward 
solving the problem of steam navigation. Just as in the 
case of the steam engine itself a considerable number of 
men made contributions to this invention. The Marquis 
de Jouffroy in France, Symington in Scotland, a.nd Fitch, 
Rumsey, Stevens and Fulton in this country, all built 
more or less successful steamboats. But just as Watt per- 
fected the steam engine, so Fulton with his now famous 
Clermont was the first inventor to perfect a steamboat 
that, against tide and wind, could propel itself at a fair 
rate of speed for any great distance. On August 7, 1807, 
this "fire-belching monster" steamed up the Hudson and 
to the amazement of all and the alarm of many made the 
trip from New York to Albany in 32 hours. Epoch mak- 
ing was this event, for it mmabered the days of the sailing 
vessel. 

Steam navigation was rapidly appKed to rivers and lakes. 
In 1809 the traveler could go by steamboat from Philadel- 
phia to Bordentown with breakfast and dinner on board. 
From there he took the stage to New Brunswick where he 
stayed overnight and continued his journey to New York 
the following day. A tedious way of travel we should say 
now and yet we can imagine the delight v/ith which it was 
hailed in those days of the stage coach and ox-cart. 



The Story of the Steam Age 205 

In 1 8 19 the Savannah, the first steamship, crossed the 
Atlantic, although not depending upon steam power alto- 
gether and using her sails for part of the voyage. In 1838 
the Sirius and the Great Western made the passage with 
steam alone. A speed of over 200 miles a day was made by 
the Great Western and about 450 tons of coal were con- 
sumed. The Britannia, the first steamship of the Cunard 
Line, started on its maiden voyage across the Atlantic on 
July 4, 1840. Very soon steel vessels began to replace the 
old wooden ships. Larger and faster ships were built. 
Screw propellers took the place of the side-wheel boats. 
The ''ocean greyhounds" appeared in 187 1 and by 1888 
the time of passage from Europe to America had been cut 
to less than six days. 

The Steam Turbine. — ^Another and more recent applica- 
tion of steam, which has had a very great influence on the 
development of ocean steamships, is the steam turbine. 
This engine makes use of the direct impact of the mole- 
cules of steam on a large number of Kttle curved blades 
attached to the circumference of a disk mounted on a long 
slender shaft. Although there are three principal types of 
steam turbines, the DeLaval, the Curtiss and the Parsons, 
they all utilize the same fundamental principle and trans- 
late the kinetic energy of the steam directly into the motion 
of the turbine. 

The turbine was invented by Mr. C. A. Parsons of Eng- 
land in 1884 and has had a very rapid development. In 
this type the rotating spindle carries several sets of blades, 
each set being longer than the preceding. The casing that 
fits over the spindle carries an equal number of sets of 
stationary blades, which dovetail in between the moving 
blades. The steam enters the turbine on the side of the 
shortest blades at a velocity frequently of 4,000 feet, or 



2o6 The Boys' Own Book of Great Inventions 

three-quarters of a mile per second. By direct impact the 
molecules of steam set the spindle rotating and the steam 
glancing from one row of moving blades is guided by the 
adjacent stationary row so that it strikes the next moving 
row at just the right angle and so on to the opposite end of 
the spindle. As the steam moves forward it expands and its 
pressure falls. Therefore, just as in the compoimd engine, 
each succeeding set of blades is longer than the set before it. 
The steam at a very low pressure passes from the large end 
of the spindle into the condensing chamber. 

In the turbine the efficiency is slightly higher than in the 
reciprocating engine. There is practically an entire absence 
of noise and vibration and the speeds obtainable are very 
great, in some small engines being as high as 30,000 revolu- 
tions per minute or 500 per second. This seems incredible 
and yet it is true. These features have especially adapted 
the turbine for use on ocean liners, and the fastest and largest 
ones are now^ equipped with this engine. Among the first 
large ships to be so equipped were the Cunard liners, 
Carmania, Mauretania and the ill-fated Lusitania. One 
objection to the turbine is the impossibility of reversing 
it and for this reason two sets of engines must be carried, 
one for direct forward motion and the other for reversing. 

The turbine is also used extensively for land installations, 
especially in electric power plants. The author saw in 
the United States Steel Company's plant at Gary, In- 
diana, a large 5,000 horse-power Curtiss steam turbine run- 
ning on waste steam obtained from the cooling water about 
the doors of the open hearth furnaces. 

The Locomotive. — ^Again just as with the steam engine 
and the steamboat to no one man is due sole credit for the 
invention of the locomotive. Before the close of the eight- 
eenth century a great variety of experimental locomotives 



The Story of the Steam Age 207 

had been built, but nothing of importance appeared until 
Trevi thick in 1802 produced a steam locomotive that suc- 
cessfully hauled a wagon load of people over the streets of 
London. Two years later he built a locomotive that was 
able to draw loads of ten tons of iron, but it was a financial 
failure and soon abandoned. 

The man who built the fitrst successful passenger carrying 
locomotive was George Stephenson. He was the son of 
poor parents and from a lad up had worked in the colliery. 
At eighteen he had risen to the position of fireman and his 
great ambition was to master the intricacies of the steam 
engine and to gain a thorough working knowledge of its 
parts. His knowledge soon became so complete that he 
undertook the building of an engine for his employers. 
The result was a locomotive that would haul a load of 
30 tons at 4 miles an hour up a grade of one foot in 450. 
His second locomotive was an improvement but still very 
imperfect. In 1825, however, Stephenson built the Rocket 
which will forever be recognized as the first thoroughly 
successful locomotive and the one that converted a long 
doubting public into rather reluctant support of steam 
locomotion. 

In 1829 the now famous Liverpool and Manchester 
Railway offered a prize of £500 for a locomotive that on a 
certain day would best perform certain specified duties. 
Stephenson entered the contest with the Rocket and in 
competition with three others established the superiority 
of his locomotive. With it he performed marvelous feats 
for those days. Carrying a load of 36 passengers he made a 
speed of 30 miles an hour and with 13 tons of freight he 
covered 35 miles including stops in one hour and forty- 
eight minutes. The world then knew that the age of steam 
locomotion had come. 



2o8 The Boys^ Own Book of Great Inventions 

The United States with its vast reaches of new country, 
its poor roads and inadequate transportation facilities 
offered a rich field for the activity of the locomotive pioneer. 
The American people were quick to appreciate the ad- 
vantages to be derived from this new means of travel and 
there began with the second quarter of the nineteenth 
century that period of railroad development which has 
been one of the marvels of modern industrial achievement. 
The first road to be operated was the Baltimore and Ohio. 
It was chartered in 1827, the ground was broken in 1828 
and the first locomotive, built by Peter Cooper, ran over it 
in 1830. In the same year six miles of the Charlestown and 
Augusta Railroad were opened and in 183 1 the Mohawk and 
Hudson Railroad began passenger service. The famous 
"John Bull" locomotive of the Camden and Amboy Rail- 
road was built in England and received in Philadelphia in 
183 1. Mr. Dripps, the master mechanic of the road, put 
it together. He found a four-wheeled car for tender, a 
whiskey cask from a nearby grocery served for water tank 
and the locomotive was soon in active service. Locomotive 
works and railroad shops sprang into existence. The me- 
chanical genius of the country devoted itseh to the im- 
provement of the original types of locomotives. Lines of 
railroad multiplied. New regions were made accessible. 
The Ohio Valley became tributary to the Atlantic Sea- 
board. In ten years 3,000 miles of steam roads were in 
operation and a period of national growth and industrial 
expansion without parallel in the world's history had been 
inaugurated. The railroads crossed the AUeghenies, 
spread like a network over the Mississippi Valley and pene- 
trated the ''Great West." They made possible a nation 
extending from ocean to ocean and when on May 10, 1869, 
the golden spikes completing the Union Pacific Railroad 




Mountain freight locomotive, "John Bull" locomotive and first engine used on 
the Denver & Rio Grande Railroad. 



The Story of the Steam Age 



209 



were driven the East and West were forever united and the 

first stage of American railroading had passed into history. 

Steam power has conquered the world. Under its 

influence industry has been revolutionized, continents 



KJ 



I 



::^ 




Fig. 74. 

spanned, oceans bridged and mountains tunneled. The 
vastness of the earth has disappeared. Natural barriers 
no longer exist. Provincial narrowness has broadened into 
cosmopolitanism. A new era of world-wide political, in- 
dustrial and social intercourse is about to dawn upon the 



2IO The Boys' Own Book of Great Inventions 



earth. But let us remember that back of this wonderful 
century of human progress stands James Watt and the 
steam engine. 

Two Experiments. — i. That heat is energy and can be 
made to do work may easily be shown by arranging ap- 
paratus as shown in Fig. 74. As the water in flask A is 
heated, the vapor and air above it expand and pressing 
downward upon its surface lift the 
water and cause it to flow in a steady 
stream into the beaker above. 

A one-holed rubber stopper must 
be used for the flask. To bend the 
glass tubing place it in a Bunsen 
burner flame (having a fish-tail top 
if possible) and rotating it rapidly 
with the thumb and forefinger 
thoroughly soften the glass. When 
this has been done remove it and 
quickly bend to the desired shape. 

2. — ^Arrange a flask carrying a 
three-holed rubber stopper with mer- 
cury pressure gauge, thermometer and 
outlet tube as shown in Fig. 75. To 
the outlet tube attach a short piece of 
rubber tubing and wire it on with pli- 
ers. On this place a screw pinch cock. 
Heat the water in the flask and when it is boiling freely 
note the temperature on the thermometer. Being open to 
the air the water will be boiling under atmospheric pres- 
sure. Now cut off the outlet by screwing down the pinch 
cock and allow the steam pressure in the flask to increase. 
Three effects will be noted. The water ceases to boil, the 
mercury rises in the open arm of the pressure gauge and the 




The Story of the Steam Age 211 

temperature indicated by the thermometer increases. The 
steam is now in the superheated condition. By allowing 
the steam to accumulate and the pressure to increase, more 
energy and a higher temperature are required to boil the 
water. The water will again start to boil but at a higher 
temperature. 

When the temperature has risen several degrees, unscrew 
the pinch cock and open the outlet. Again three effects 
will be noted. The mercury falls in the pressure gauge, 
the thermometer suddenly drops to the former boiling point 
and the pent up heat energy in the water manifests itseK 
by causing an exceedingly vigorous boihng. This energy is 
expended in a very rapid transformation of water into steam. 

The high pressure steam used in engines is superheated in 
this same way. 

As it is usually impossible to buy three-holed rubber 
stoppers, a two-holed stopper may have an additional hole 
bored with cork borers. To do this select a borer of proper 
size, cover the lower end with thin soap paste or dip it in 
a strong solution of washing soda and with the large end of 
the stopper resting on a solid support drill the hole. 



Chapter XII 

SOLVING THE SMALL POWER PROBLEM 

If we were to single out any one invention of the last 
forty years and designate it as having been in larger meas- 
ure than any other of fundamental importance to the won- 
derful progress of this period, we should unhesitatingly 
name the gas engine, or internal combustion motor. And we 
say fundamental because so many other of the epoch mak- 
ing inventions of this period are dependent upon it and 
were impossible imtil it came. A Httle consideration of 
what the gas engine has done will make this evident. It 
has made possible the automobile, the aeroplane and air- 
ship, the submarine, the motor boat, the farm tractor, the 
army motor truck, the motor-cycle, the small power and 
electric Hght plant with all that these inventions have meant 
for weal or woe to the commercial expansion, comfort and 
happiness of the world. The gasoline motor, the most im- 
portant type of this class of engines, with a rapidity never 
before equaled, has come into universal use. It has 
touched the Hves of the common people at innumerable 
points and has met with perfect satisfaction a host of very 
real needs. Just reflect for a moment upon what the world 
would have missed during the last twenty-five years with 
out this wonderfully efficient, Hght and powerful Httle 
motor and you wiU only just begin to appreciate its im- 
mense importance to the modem world. The steam engine 
met the big power needs but not the Kttle ones. It was not 
every man's engine. There was still a multitude of tasks 

212 



Solving the Small Power Problem 213 

that it could not perform. It was not light, compact and 
portable with steam always up and ready to start at a 
moment's notice. But just when the steam engine was 
approaching the limits of mechanical perfection and for 
nearly a century had been solving the big power problems 
of the world, there came this miracle of modem invention 
to reheve still further the drudgery of mankind. 

Seldom does one inventor enjoy the monopoly of any 
particular field of investigation. Numerous experimenters 
are always at work entirely independently of each other 
and long periods of research and many crude imperfect 
models usually precede the production of a practical and 
successful machine. To this rule the gas engine is no ex- 
ception. As early as 1807 Sir George Cayley, who also 
worked out the principles of aviation, devised a hot air 
engine, but the mechanical difficulties were insurmountable 
and it had no commercial success. In 1824 and later in 
1852 John Ericsson, who built the famous iron-clad moni- 
tor during the Civil War, constructed hot air engines of 
considerable size, but they were of small horse power and 
did not prove successful. Even as early as the seventeenth 
century the Dutch scientist, Huyghens, and the French- 
man Papin, endeavored to utilize the mechanical energy 
of exploding gunpowder to operate an engine but without 
practical result. The first man to invent a real gas engine 
was the Frenchman J. J. E. Lenoir, who in i860 patented 
an engine on the plan of its steam predecessor. The first 
commercially successful gas engine, however, and the 
modern four-stroke motor was invented by two Germans, 
Otto and Langen, in 1866. A very great improvement was 
made by Otto in 1876, when he introduced the expedient of 
compressing the mixture of gas and air before exploding it. 
This added very much to the power and efficiency of the 



214 The Boys' Own Book of Great Inventions 

engine and when a little later it was found that liquid 
fuel could be substituted for gas, the new era of the Hght 
weight, high speed gasoline motor was at hand. The 
Diesel engine, employing heavier oils than gasoline, is de- 
scribed under the submarine. 

The fundamental difference between the steam engine 
and the gasoHne motor is in the liberation and transmis- 
sion of the energy that drives them. In the steam engine 
the energy of the burning fuel is transferred into the steam 
of the boihng water and transmitted to the working cyl- 
inder where by impact and expansion it drives the piston. 
But in the internal combustion engine, as its name signifies, 
the energy from the exploded mixture of fuel and air is 
liberated right in the cylinder and immediately exerts the 
kinetic energy of its moving molecules directly upon the 
piston-head. This is one of the chief reasons for the higher 
efficiency of the gasoline engine. Nothing intervenes be- 
tween the Hberation of the heat energy and its application. 
But the steam engine wastes heat. Not all of the energy in 
the coal gets into the water. The firebox and hot cHnkers 
radiate to the air a great deal of heat. The boiler radiates 
more and the steam pipe and cylinder of the engine do the 
same. All the steam that escapes to the condenser carries 
away just that much energy, and the hot combustion gases 
from the firebox carry up the stack far more energy than 
is transmitted to the water. At best only a small portion 
of the energy in the fuel is caught and turned into power 
units by the engine. Then, too, of the horse power de- 
livered by any engine there are large losses in transmis- 
sion to moving machinery. The percentage of the original 
energy that is finally translated into really useful work is 
exceedingly small. And although this lost energy is not de- 
stroyed, it is wasted and so far as we are able to see will 



Solving the Small Power Problem 215 

never again be available for doing useful work on this 
planet. It has been absorbed by the great ocean of ether 
that surrounds us. That there should be in spite of such 
appalling waste, sources of energy sufficient for the world's 
needs throughout the centuries that have been and are to 
be, testifies to the prodigality of nature as nothing else 
could. 

There are two general types of the gas engine, the two- 
cycle and the four-cycle, or better the two-stroke and the 
four-stroke. In the former case an explosion occurs every 
revolution, or every two strokes of the piston, while in the 
latter there is an explosion but once for every two revolu- 
tions, or four strokes. With the two-cycle engine the crank 
shaft receives an impulse at each revolution, while with the 
four-cycle engine the impulses are only half as frequent, there 
being but one for every two revolutions. The two-cycle 
engine would seem to be more efiicient and to develop more 
power, but such is not the case. It does run more smoothly 
and with less vibration and does not require so heavy a 
flywheel as the four-cycle, but for reasons that will be ap- 
parent later it is not so well adapted to large power needs. 
For motor boats and the mmierous uses to which small 
motors are put the two-cycle engine has been very popular. 

The Two-Cycle Engine. — The construction and operation 
of a two-cycle engine will become apparent from a consider- 
ation of the diagrams in Fig. 76. We will start with the 
piston as shown in position A and the cyhnder free from gas. 
If we turn the crank shaft in the direction indicated by the 
arrow, when the piston has reached the lowest point of 
the stroke and begins to move upward a partial vacuum 
will be created in the engine base B and through the valve 
Va mixture of gas and air from the carburetor will be 
punaped in. Then as the piston moves downward the gas 





D 



Fig. 76. — The two-cycle gas engine. 



Solving the Small Power Problem 217 

in the engine base is compressed and the valve V closed. 
When the piston has moved to the bottom of the stroke 
the intake port I is uncovered and the mixture in the bot- 
tom being imder pressure is forced upward through the 
by-pass P into the cylinder above. It is prevented from 
passing directly across and escaping through the exhaust 
port by the deflector on the piston-head. As the piston now 
moves upward, as shown at D, both ports are closed and the 
gas in the cylinder is compressed. When the piston reaches 
the top of the stroke an electric spark across the terminals 
of the spark plug ignites the mixture and the large vokune 
of very hot gases which results forces the piston downward. 
As the piston moves downward the exhaust port is uncov- 
ered, first allowing the combustion gases to escape, and im- 
mediately following the intake port is uncovered, drawing 
a fresh mixture into the cylinder. This condition is shown 
at C. The momentum of the flywheel carries the piston 
upward and at the top of the stroke a second explosion 
occurs with the repetition of the "cycles" of change. Thus 
there are only two cycles, the compression stroke and the 
firing stroke. On the upstroke a fresh mixture of gas and 
air is drawn into the engine base below and the mixture 
above is compressed. On the firing stroke the hot combus- 
tion gases expand, shooting the piston down and compressing 
the mixture below. The compression of the mixture in the 
cylinder on the upstroke, however, is several times greater 
than it is in the engine base on the downstroke. 

While the two-cycle engine is very simple in construction 
and operation, it will be seen that a full charge of fresh 
mixture uncontaminated with burnt gases is difficult to 
secure. The burnt gases leave the cyhnder from their 
own expansion and some will always be left to mix with the 
fresh charge. The amount may be considerable and to just 



2i8 The Boys' Own Book of Great Inventions 

that extent dilutes the charge and lessens the energy 
liberated on the explosion. Then, too', in spite of the de- 
flector on the piston-head a portion of the incoming gas 
may escape with the exhaust gases and this loss will lower 
the efficiency. To build a two-cycle engine is a more dif- 
ficult task and requires more accurate designing than the 
construction of a four-cycle engine. Therefore for most 
purposes the latter type of engine has been adopted. 

The Four-Cycle Engine. — The operation of the four- 
cycle engine is shown in Fig. 77. It will be noted that the 
intake and exhaust ports are opened and closed by tight- 
fitting valves instead of by the movement of the piston over 
them. Starting with the suction, or charging stroke, the 
intake valve opens and the piston moving toward the open 
end of the cylinder draws in a charge of gas and air from the 
carburetor. At the end of the stroke the intake valve 
closes and the piston moving backward compresses the 
explosive mixture to small volimie. At the point of maxi- 
mimi compression a spark across the terminals of the spark 
plug ignites the mixture and the piston is forced outward. 
Just before the end of the expansion stroke the exhaust 
valve is lifted and as the piston moves backward the burnt 
gases are swept from the cylinder. At the end of the stroke 
the exhaust valve closes and the cycle of changes is re- 
peated; thus there is but one power stroke for two revolu- 
tions and to carry the piston through the idle strokes a 
heavy flywheel is required. 

In the early engines the intake valve was opened by the 
suction from the charging stroke, but both intake and ex- 
haust valves are now operated by cams and push-rods. 
The cam for this purpose is a small metal disk mounted on a 
shaft and having a projection on one side. This shaft is 
geared to the flywheel shaft so that it will turn only once 



Solving the Small Power Problem 



219 



>A(}missiOR 




c- — ^Admission 



Beginning 
'Exhaust 
THE SUCTION STROKE 

-Admission 




Beginning 
Exhaust 
THE EXPANSION STROKE 
Admission 




-Admission 




■< — Admission 



Beginning 
■Exhaust 
THE COMPRESSION STROKE 
-Admission 





Beginning 
Exhaust 
THE EXHAUST STROKE 
Admbsion 




Ending 
Exhaust 
Fig. 77. — The four-cycle gas engine. 

for every two revolutions of the main shaft. At the proper 
instant for the opening of the valve the projection on the 
cam disk strikes on the push-rod and lifts the valve. A 
spring brings the push-rod back and the valve closes. 



220 The Boys' Own Book of Great Inventions 

It would be impossible to make a plain smooth piston 
that would be perfectly gas tight under the very great pres- 
sures developed in the cylinder of a gas engine. Therefore 
pistons are made with several grooves cut in them into 
which piston rings are fitted. A piston ring does not form 
a complete circle. The ends do not quite meet and the ring 
is made sKghtly larger than the inside of the cylinder. As 
these rings expand they press snugly against the walls of 
the cyhnder and prevent the gas from leaking out. Pistons, 
rings and cylinders must be exceedingly true and to make 
them so has been one of the most important points in gas 
engine construction. Any leakage results in loss of compres- 
sion and diminished power. 

The heat generated by the combustion in the cylinder is 
so great that its walls and the piston would become red 
hot if some provision were not made to cool them. Many 
two-cycle engines are air-cooled. The cylinder is ribbed 
to present a large radiating surface and the flywheel 
shaped like a fan drives a current of air over the hot parts. 
A water jacket surrounds the cyhnder of a four-cycle 
engine and either by pump or natural circulation water is 
made to flow about the cylinder to carry away the excess 
heat. Of course all the heat carried away in this manner is 
lost energy, but it cannot be avoided. 

The Carburetor. — The carburetor is the mechanism in 
which the gasoline vapor and air are mixed in proper pro- 
portions to form a highly explosive mixture. In Fig. 78 
are shown a diagram of a simple carburetor and the/' model 
A" Shebler carburetor. The gasoline flowing downward 
from tank T enters the float chamber and lifting the float 
F, which may be either of cork or a hollow metal float, 
closes the needle valve. The gasoline rises to the top of the 
spray nozzle S and the air being drawn in by the suction 




Fig. 78.— The carburetor. 



222 The Boys^ Own Book of Great Inventions 

from the cylinder vaporizes the gasoline and mixing with 
it passes on to the intake manifold of the engine. As the 
gasoline is used up the float falls, admitting more gasoline 
and thus the supply is automatically regulated. The intake 
of air can be controlled by the check valve C. When the 
engine is nmning rapidly and working hard not enough air 
is supplied through the main inlet and therefore an auxil- 
iary air inlet is provided at A. Under these conditions the 
suction increases and becomes strong enough to open the 
valve at A and draw in an additional supply of air. By 
suction is of course meant the diminished pressure in the 
engine cylinder produced by the charging stroke. The 
quantity of gases admitted to the cylinder can be regulated 
by adjusting the throttle valve M. This is frequently done 
automatically by a governor and the speed of the engine 
thereby controlled. For increasing the supply of gasoline 
as is sometimes required in starting an engine the small 
priming pin resting on the top of the float may be forced 
down, thereby opening the needle valve. Upon the proper 
adjustment of the carburetor depends the proportions of 
gas and air and the explosive qualities of the mixture. 
Therefore to a very large extent the efficiency of the engine 
is a function of the carburetor. 

The Ignition System. — To produce the spark necessary 
to ignite the mixture of gas and air two main systems are 
employed — the storage battery and induction coil and the 
magneto system. The construction and action of both the 
storage battery and induction coil are explained ui other 
portions of this book and it will be assumed that their use 
is imder stood. A simple ignition system of the first type 
is shown in Fig. 79. The main shaft is represented at W 
and geared to this is the cam shaft W. The number of cogs 
on the main shaft is half that on the cam shaft and there- 



Solving the Small Power Problem 



223 



fore the latter makes only one revolution for every two of 
the main shaft. An insulating disk D is mounted on the 
cam shaft carrying a brass contact and screw at K. Back 
of this disk is mounted a movable plate M. P. which car- 




FiG. 79. — A simple ignition-system. 

ries a metallic block B held against the disk by means of a 
spring. Now as the cam shaft revolves the contact K and 
the block B will be brought together thus completing the 
circuit through the switch S, the storage batteries S. B. 
and the primary of the induction coil C. This will induce 
a high electromotive force in the secondary of the induction 
coil, the terminals of which go to the insulated rod in the 



224 The Boys' Own Book of Great Inventions 

spark plug and the cylinder of the engine. As the contact 
K moves by the block and the circuit is broken, a spark leaps 
across the gap inside the cylinder and the mixture is fired. 
The spring and block B are insulated at I from the movable 
plate and therefore the circuit can be made only when K 
and B are in contact. Since this happens only once during 
each two revolutions of the main shaft there will be but 
one spark during this time, as the four-cycle engine requires. 
The position of the block B may be adjusted by moving 
the lever L and, therefore, the spark may be timed to the 
exact instant of maximum compression. 

A magneto is frequently substituted for the storage 
batteries. A magneto is a small generator employing per- 
manent field magnets instead of electromagnets and belted 
to the main shaft of the engine. If this is substituted for 
the batteries whenever the contact is made at B a current 
will flow through the induction coil and a spark will result 
as before. 

In the magneto system proper, however, a high tension 
generator is employed and both the storage batteries and 
induction coil are dispensed with. The armature of a high 
tension magneto has two windings, a primary of coarse 
wire and a secondary of fine wire just as an induction coil 
has. The terminals of the primary winding are connected 
with the block B and the movable plate just as before, while 
the secondary winding is connected through a condenser 
with the spark plug. As the current in the primary is made 
and broken at B the high electromotive force induced in 
the secondary charges the condenser and this immediately 
discharges across the terminals of the spark plug and ignites 
the mixture. When the engine has more than one cylinder 
in addition to the timing device for producing a spark at 
the instant of maximum compression in each cylinder, 



. Solving the Small Power Problem 225 

there must also be placed in the secondary circuit a dis- 
tributor to throw the spark to the proper cylinder. 

Gas Engine Development. — In early gas engine construc- 
tion it was sought to secure increased power by increasing 
the size of the cyHnder, but it was soon found that this could 
be accompHshed to much better advantage by employing 
several cylmders instead of one. Very soon the four- 
cylinder engine came into general use and now we have en- 
gines with six, eight and twelve cyHnders. By increasing 
the number of cylinders the number of explosions per 
revolution is increased and therefore the impulses acting 
upon the crank shaft are more frequent. In a four-cylinder 
engine there are four explosions and resultant impulses for 
every two revolutions, or one explosion for each half revo- 
lution. A more uniform development of power results. 
There is less vibration. Lighter flywheels and Kghter con- 
struction throughout can be employed. 

The wonderful development of the aeroplane has been 
dependent upon the construction of Hght-weight high-power 
engines and one of the greatest recent achievements has 
been in this direction. A recent Duesenberg model weighs 
about 33^ pounds per horse power and one of the new aero- 
plane motors of the B. F. Sturtevant Company develops 
one horse power for each 2.3 pounds of weight. The famous 
French Gnome engine and the similar Gyro engine made in 
this country are light powerful engines of the rotating 
cylinder type with which many of the altitude and speed 
records have been made. The Gyro engine develops no 
horse power and weighs but 270 pounds. The new Liberty 
motors develop over 400 horse power and the bombing 
planes which the Handley Page Company proposes to 
build and fly across the Atlantic are equipped with two of 
these motors. The new type of ZeppeKn carries six 250- 



226 The Boys' Own Book of Great Inventions 

horse power motors. The carburetors of aeroplane engines 
are now equipped with an automatic compensating device 
which prevents a change in the quality of the mixture with 
varying altitudes. 

One of the greatest present needs of the petrol motor is a 
carburetor that will make possible the use of heavier oils. 
Very marked advancement has been made in this direction 
and a grade of gasoline is of necessity used now that would 
have been impossible a few years ago. But if kerosene, 
benzol and alcohol are to come into general use still fur- 
ther improvment must be made and there is no doubt but 
that it will be. 

One very important application of the gas engine as dis- 
tinguished from the gasoline, or petrol, motor has been in 
the natural gas fields and in connection with producer- 
gas plants. The gas engine has adapted itself to large 
power purposes and where natural gas is available it has 
given very cheap power. It has been foimd, too, in many 
instances that it is cleaner, more economical and more 
efficient to convert the carbon of coal into producer gas 
and bum it in a gas engine than it is to bum the coal 
under a steam boiler and employ a steam engine. 

The Automobile. — ^The most fitting symbol of the Twen- 
tieth Century spirit is locomotion. For forty years steam 
and electric locomotives, bicycles, motor cars, airships, 
aeroplanes and submarines have been following each other 
with almost bewildering rapidity. Transportation has 
expanded to embrace not only the surface of the earth but 
the heavens above and the depths below. The conquest 
of time and space has become a passion with the race. 
These natural barriers, suffering assault after assault, are 
dwindling to the vanishing point. Every day this planet 
grows smaller. Isolation is disappearing and in this freer 




The Haynes automobile on the streets of Chicago in 1895 and the first Stanley 

Steamer. 



Solving the Small Power Problem 227 

intercourse of men and nations lies the future hope of world 
peace. 

To this. rapid extension of the means of travel nothing 
has contributed more than the motor car. This application 
of the gasoline engine has spelled transportation for the 
common man. It has promoted travel, stimulated busi- 
ness, made the nation more efficient, simphfied recreation 
and as Dr. Frank Crane says, ''made life richer, freer 
and happier." 

The first four-wheeled vehicle to be propelled by a gaso- 
line motor was made in France by Messrs. Pannard and 
Levassor in 1889 and with marvelous rapidity the motor 
age was ushered in. Seldom has the adaptation of a great 
invention made so universal a conquest in so short a 
time. 

In this country, George B. Selden in 1879 applied for a 
patent to cover the use of the gas engine in road vehicles, 
but the patent was not issued until 1895. ^^ the mean- 
time Elwood Haynes of Kokomo, Indiana, had been ex- 
perimenting along similar lines and in 1893 built Amer- 
ica's first successful automobile. The first actual run of the 
car was made in Kokomo, July 4, 1894. The car driven by 
an engine that weighed 180 pounds and developed one horse 
power made the ''exceptional" speed of 63^ miles an hour 
and covered 28 miles on a gallon of 8 cent gasoline. This 
car is now on exhibition in the Smithsonian Institution. 
The brothers F. E. and F. 0. Stanley in 1897 built a steam 
car which in the following year and again in 1906 estab- 
Hshed new speed records. In many respects steam is the 
ideal power for the automobile and the Stanley steamers 
are still widely used. 

A few facts will show the wonderful growth of the auto- 
mobile industry. The first automobile was sold in the 



228 The Boys' Own Book of Great Inventions 

United States in 1896 — 22 years ago. To-day there is one 
automobile for every 24 of the population or one to every 
fifth family. The automobile business is the third largest 
industry in the country and employs 5 per cent of the whole 
population. There are $736,000,000 of capital invested 
in the industry, and the annual volume of business is nearly 
a billion dollars. There are 4,000,000 passenger cars in the 
country covering 60,000,000,000 passenger miles per year 
which service at 2 cents per mile would cost $1,200,000,000. 
The passenger mileage of the automobiles of the country is 
greater than that of all the steam and electric roads com- 
bined. And yet the automobile is not a competitor of 
railroads and traction Hnes. It has developed an independ- 
ent traffic, hitherto non-existent, and is their greatest 
feeder. Taxed to their utmost and more, the railroads 
would be overwhelmed without the motor car. 

The automobile and the tractor have revolutionized 
farm practice. Market and farm have been brought to- 
gether. Time and energy have been saved. The man power 
engaged in agriculture has been multiplied and the labor 
problem largely solved. Horses on the farm are becoming 
obsolete and like the sickle and the flail will soon be relics 
of the past. The 35,000,000 bushels of food which they 
eat per year will help to feed the starving populations of 
the earth. Fifty thousand farm tractors were in use in 
this country at the beginning of 19 17 and as many more 
were built in that year. What the coimtry needs is a cheap 
tractor and the genius of a Henry Ford applied to its man- 
ufacture and distribution. A tractor for $250 would enable 
this country to feed the world. 

The army motor truck and the military tractor are the 
motive power of a modern army. In the spring of 19 14, 
just before the Great War, Germany mobilized the motor 



Solving the Small Power Problem 229 

cars of the Empire for the treacherous attack on the peace 
of the world which she had so foully planned. She had the 
Allies at a tremendous disadvantage and it was only by 
pressing into service every motor car, truck and taxicab 
found on the streets of Paris that Joffre was able to support 
his army at the Marne. Transportation faciUties are in- 
dispensable to successful field operations. An army can 
advance no faster than its artillery can be moved forward. 
During the first four years of the war the artillery tractors 
have been able to travel barely three miles an hour, but the 
United States has produced a giant tractor that will double 
the speed and that, too, over the roughest shell-torn battle 
field. Fallen trees and deep holes are no obstacle to its 
progress. 

The motor car service and strategic railroads of Ger- 
many were of the greatest assistance in her early successes. 
But the AUies were quick to motorize their armies. At 
Verdun, when the German artillery had destroyed the rail- 
road communications, the motor trucks took their place, 
and without this aid the glorious resistance of the men who 
said, ''they shall not pass" would have been impossible. 
The rebuilding of roads and bridges waits upon motor 
truck transportation of supplies. Rapid motor transport 
of the wounded from the battle front saves many lives to the 
army and the home. The transport of troops from front 
to front multiplies the efficiency of the reserves. The motor 
requirements of the United States Army in France for 
19 18 are 100,000 trucks which including repairs will cost 
$400,000,000. The cost of the war is prodigious, but the 
liberties of the earth are worth its last resource. 

Thus in peace and war the wonderfully efficient, light 
but powerful gasoline motor has made a record for service 
unmatched by any other invention of modern times. 



230 The Boys^ Own Book of Great Inventions 



A GAS EXPLOSION 



Borrow a large Woulf bottle from the high school labora- 
tory or procure a gallon can and cut another hole in the 
top. Fit the necks of the bottle or the holes in the can with 



^ 




c " 




6AS 



Fig. 80. 



one-holed stoppers carrying glass tubes as shown in the 
diagram. The tube BC should be of fairly large diameter. 
Connect the bent tube A with a gas cock by means of rub- 
ber tubing and turning on the gas drive out the air from the 



Solving the Small Power Problem 231 

bottle. Light the gas at B and then withdraw tube A 
with its stopper, at the same time turning off the gas, but 
do not stop the flow of gas until the stopper has been par- 
tially removed. The gas will continue to bum at B with 
a small flame for some time and then seem to disappear en- 
tirely. Do not conclude that the experiment is a failure 
but wait and suddenly a very sharp report will occur and 
the bottle will be filled with a sheet of flame. If done at 
night or in a darkened room the effect is heightened. 

As the gas escapes and burns at B, air enters through the 
open neck until the bottle is full of an explosive mixture 
of gas and air, when the feeble flame at B will strike down 
into the mixture producing the explosion. This is the same 
as the ''striking back" of a hot plate or gas stove, and aside 
from the fact that there is no compression it is the same as 
the explosion in the cylinder of a gas engine. 



Chapter XIII 

A CENTURY OF AGRICULTURAL PROGRESS 

Difficult as it may seem for many of us to believe, the 
greatest problem of all nations has been to make this old 
earth yield enough of food stuffs to satisfy the hunger of 
the many milhons that inhabit it. Especially has this been 
true during the Great War and most keenly have people 
everywhere been brought to realize it. Yet until compara- 
tively recently the genius of the race has not been directed 
toward improving methods of agriculture. Labor-saving 
devices for multiplying the man power and efficiency of the 
artisan and mechanic began to appear, but the farmer 
plodded on in the primitive ways of his fathers. McMaster, 
in his '^History of the People of the United States," says, 
''The Massachusetts farmer who witnessed the revolution 
plowed his land with a wooden bull plow, sowed his grain 
broadcast, and, when it was ripe cut it with a scythe and 
threshed it out on his floor with a flail." Each householder 
was almost entirely self-sustaining, producing nearly all 
that he and his family required. He sold but little and 
bought less. There was no need for producing more, and a 
virgin soil and large crops did not stimulate inventive genius 
along agricultural lines. But with the building of cities, 
the growth of manufacturing and the great divisions of 
labor it became imperative that the farmer should provide 
food, not only for his own family, but for the ever increas- 
ing army of those not engaged in agriculture. To do this 
brought profits, and the incentive of private gain encouraged 

232 



A Century of Agricultural Progress 233 

efforts toward increased productiveness and the develop- 
ment of new devices and better methods. 

No more interesting chapter in agricultural growth can 
be found than that which tells the story of harvesting 
machinery. From the ancient Eygptians down to the be- 
ginning of the last century the reaping hook, or sickle, 
was the sole means of cutting grain. These early imple- 
ments were made of flint and bronze. Pictures upon the 
tombs at Thebes show slaves using these crude tools. 
Later iron and steel came into use, but not until the last 
century was any substantial progress made in improving 
harvesting machinery. 

The scythe, still a familiar tool on all farms, was the first 
development from the sickle. It differs from it in that it 
enabled the operator to use both hands instead of one. 
A clumsy, heavy instrimient at first, the blade of the scythe 
was gradually made hghter, the handle lengthened, and 
fingers were added to collect the grain and carry it to the 
end of the stroke, so that it might be laid in a swath for 
dr}dng and made ready for the binder. This tool is dis- 
tinctly an American development and was given the name 
cradle. It was introduced during the last quarter of the 
eighteenth century and very rapidly spread to all countries. 
No other hand tool has been devised that equals it for the 
harvesting of grain. Whereas with the sickle it required 
seven men to cut, bind and shock two acres of grain per day 
the use of the cradle enabled two men to do the same 
amount. Its use, too, has not yet passed, for there are 
places where the land will not permit of the use of reapers 
and the cradle is the only practicable instrument. 

The first practical efforts toward harvesting wholly by 
mechanical means began about the year 1800. Some at- 
tempts in this direction had been made by the Gauls and 



234 The Boys' Own Book of Great Inventions 

Romans nearly two thousand years before but nothing of 
permanent value resulted. Just preceding and following 
the year 1800 a number of patents were granted in England 
to inventors of reaping machines. But all of these were un- 
successful, for as late as 185 1 at the World's Fair in London 
the United Kingdom was unable to exhibit a reaping ma- 
chine. For the solution of the harvesting problem the 
world turned to America, but up to 1831 no practical, work- 
ing reaper had been developed. In that year came the Mc- 
Cormick. It was the first successful machine ever used, and, 
although crude at first, it was rapidly improved. Built in 
an old blacksmith shop near Steele's Tavern, Virginia, 
early in the fall of 1831 Cyrus McCormick hitched four 
horses to his machine and drove into a field of oats on the 
farm of John Steele. Great interest marked the event and 
a large company of neighbors witnessed the performance. 
This was the first grain ever cut by machinery. In less 
than half a day, to the amazement of everyone, six acres 
had been reaped, or as much as six men would have done 
in a whole day by the old-fashioned method. The intro- 
duction of the reaper markes a turning point in agricultural 
progress. Nothing of similar importance in this field had oc- 
curred in more than two thousand years. Like all other 
labor-saving machines it increased production and de- 
creased its cost, giving the world a tremendous start toward 
cheaper bread. 

Strange as it may seem, ten years passed before McCor- 
mick was able to make his first sale. Two years later 
twenty more were sold and in 1844 fifty. He continued 
to improve his machine and in 1845 went to Chicago where 
in 1847 he built a factory and started the world's greatest 
reaper works. 

The first machine had a platform for receiving the grain, 



A Century of AgriaiUural Progress 235 

a knife for cutting it and a reel to gather it. The driver 
rode one of the horses while another man walked beside 
the machine and raked off the grain. A little later a seat 
was added for the raker and then an automatic rake, an- 
other labor-saving device. 

From 1857 to 1870 a number of other men, among 
them W. H. Kirby, D. M. Osborne, and William N. Whitely 
secured patents on improved reapers and formed companies 
for their manufacture. But up to this time no one had 
been able to devise a successful binder for the reaper. The 
grain was cut and raked off, or ''dropped" in bundles, 
after which it had to be bound by hand. The first attempt 
at solving this problem was made by two farmer boys of 
DeKalb, Illinois, the Marsh brothers. They devised means 
to lift the grain to a table where two men, who rode on the 
machine, bound the bundles and dropped them to the 
ground. Up to 1879 about 100,000 machines of this type 
had been built and sold. 

The next development was the self-binder. Many in- 
ventors worked upon the problem and, necessity being so 
great, its solution was not long delayed. In 1865 S. D. 
Locke secured a patent which was developed into the With- 
ington wire binder and was first manufactured by Mc- 
Cormick in 1875. The device consisted of two steel fingers 
that moved back and forth and twisted a wire band about 
each bundle of grain. 

The wire binder, however, was not popular with the 
farmers and in 1878 John F. Appleby perfected a twine 
binder attachment. Its steel arms would pass a cord about 
a sheaf of grain, tie a knot, cut the cord and throw off the 
bundle. Here at last was what the world needed. The 
mechanism worked perfectly and was quickly adopted by 
the leading manufacturers of harvesting machinery. The 



236 The Boys^ Own Book of Great Inventions 

necessity for cheap twine was met through the enterprise 
of WiUiam Deering, a prominent manufacturer of twine 
binders. He persuaded Edwin H. Filter of Philadelphia, 
one of the largest twine manufacturers in this coimtry, to 
make a single strand binder twine. 

The reaper as thus developed is the reaper of to-day. 
Improvements designed to make the machine mere durable 
and reliable, Hghter to draw and requiring fewer field la- 
borers have been added. One of the latest improvements 
is the hitching device which makes possible the hauling of 
two or more binders by a single tractor. Control devices 
enable the man who sits on the binder seat to operate the 
tractor. Attachments have also been added for placing the 
grain in shocks, thus doing away with the necessity of hav- 
ing men follow the machine in the field. 

Two outgrowths of the binder are the header and the 
harvester-thresher. In the modem header the horses push 
the machine from behind and the cutting knives in front 
of the wheels drop the grain on to an endless conveyer 
which elevates it to a wagon drawn beside the machine. 
Only the heads and upper portion of the stalks are cut. 
The cutting widths are 10, 12 and 14 feet. 

In the early days and even now in some parts of the 
world threshing was accomplished by pounding out the 
grain from the straw by means of a club called a flail. In 
China oxen are driven over the straw placed on a hard 
floor and the tread of their feet separates the grain. When 
the farmer was required to produce no more than was 
sufficient for his own needs such primitive methods passed 
as satisfactory. But with an ever increasing demand for 
bread and with improved methods of cultivation and reap- 
ing a more rapid means of separating the grain became a 
necessity. And the race has always had a way of solving 




From the hand cradle to the harvester-reaper and thresher. 



A Century of Agricultural Progress 237 

such problems. In this case the answer was the modem 
thresher, or grain separator, run by a steam or gasoline en- 
gine and capable of threshing out more than one thousand 
bushels of wheat per day. And then for the big wheat farms 
of the West came the combined harvester- thresher drawn in 
some cases by from twenty to thirty horses or mules and in 
others by several powerful tractors. A single one of these 
machines and four men will reap, thresh and bag from two 
to three thousand bushels of wheat in a day. 

Thus in little more than half a century the methods of 
harvesting were entirely revolutionized and more progress 
made than in all the centuries that had preceded. When 
we consider that agriculture is the basic industry without 
which the race would starve, we see the immense signifi- 
cance of all this. Anything which increases the output of 
the soil lessens the world's hunger and makes possible the 
present highly organized state of society and industry by 
which so large a percentage of the people must be fed through 
the efforts of a comparatively few. According to the 
census of 19 10 there were engaged in agriculture in the 
United States 32^^ per cent of the population or, in other 
words, about one-third of the population feed the whole. 
And not only this but they produce large quantities of 
food stuffs in excess of our own needs for export to foreign 
nations. 

But it is not alone in the harvesting industry that agri- 
cultural progress has been made. From the wooden bull 
plow and small acreage of the revolutionary days to the 
large tractor-drawn gang plows and vast fields of the middle 
West we pass over a period of marvelous expansion. A 
century ago and less all farm work was done by hand. 
Cultivating, planting, mowing, haying, harvesting — all 
were accomplished by man power. But for all this work 



238 The Boys^ Own Book of Great Inventions 

machinery was gradually evolved. For many years the 
faithful horse was harnessed to the operation of it, but now 
the gasoline and steam tractors are taking his place. A 
single tractor, operated by one man does the work of seven 
horses. With it he will plow as high as twelve acres in a 
day or cultivate from sixteen to twenty acres. Tractor- 
drav/n seed drills, planters, cultivators, mowing machines 
and harvesters have multiplied many times the man power 
engaged in agriculture and are affording the best solution 
of the farm labor problem. By increasing the output of 
our farms and at the same time decreasing the cost for 
labor this application of the universal gasoline engine to 
farm needs is of tremendous importance. A modem tractor 
is as powerful as five horses, as enduring as seven, costs 
less than four horses, requires less care than one horse, 
occupies less room than one horse and eats only when it 
works. 

In the dairy branch of the agricultural industry to take 
the place of hand milking has come the power-driven milk- 
ing machine, a single machine operating upon two cows at 
once and doing the work with much greater rapidity and 
thoroughness. The old-fashioned method of setting the 
milk in pans and waiting for the cream to rise, followed by 
hand skimming, has been almost entirely displaced by the 
cream separator which, either hand or motor driven, does 
in a few minutes work that formerly required from twelve 
to fifteen hours and with greater efficiency. 

Modern inventions have completely revolutionized farm 
practice, and nothing has contributed more to increase 
its efficiency and to brighten the lives of those engaged in 
this most useful of all industries than the modem electric 
power and light plant. The farm to-day may have all the 
conveniencies of the city with the glorious freedom of a life 




The farm tractor and the portable electric motor. 



A Century of Agricultural Progress 239 

in the open. Light, air, power make a combination irresisti- 
ble in the promotion of happiness and prosperity. But back 
of it all stand the gasoline engine, the dynamo, the storage 
cell, the motor and the electric Hght, inventions that have 
been made in the last forty years. The gasoline engine 
drives the dynamo which generates current to charge the 
cells, and then this wonderful energy can be wired to any 
part of the house or outbuildings where it may be had by 
the pressing of a button or the throwing of a switch. It is 
thrown on or off at a moment's notice and is used only as 
need requires. The accompanying photographs show its 
many applications. It lightens the work of the housewife, 
adds comfort to the home, keeps the boys and girls con- 
tented on the farm and is a tremendous factor in dispelling 
the gloom and drudgery of farm life. 

And then there is the automobile, that marvelous com- 
bination of luxury and utility, which has done more to 
hitch the farmer's *' wagon to a star" than any other single 
invention. As Dr. Frank Crane says, *'The automobile has 
made Hfe richer, freer and happier. " But for no one more 
than the farmer. It has widened his horizon, added to his 
prosperity and multiplied his means of recreation. 

But we must not forget the telephone and free rural mail 
service which have been such tremendous factors in banish- 
ing the farmer's isolation. The daily paper and the abun- 
dance of agricultural and other literature which come to 
his household have educated him not only socially and 
politically but professionally as well, for farming is now a 
profession. It has ceased to afford a calling to anyone who 
can do nothing else. It is a science, an industry reborn 
through the brains and inventive genius of America. 



240 The Boys' Own Book of Great Inventions 

EXPERIMENTS 

1. Testing for Acids. — Place strips of blue and red litmus 
paper into vinegar, lemon juice, orange juice and solutions 
of alum and cream of tartar. To obtain a solution place a 
little of the substance to be dissolved in a test tube or small 
dish and cover well with water. Shake vigorously and warm 
if necessary to hasten the process. 

In each of these cases the blue litmus will turn red and 
the red litmus will be unaffected. This is the test for an 
acid and many more substances may be tested in a similar 
manner. 

2. Testing for Alkalies. — Make similar tests with solu- 
tions of soap, baking soda, washing soda, lye and borax. 
These substances turn red litmus blue. This is the test for 
an alkali, or a base, as it is called in chenaistry. 

3. Acid and Alkaline Soils. — Moisten samples of various 
kinds of soils and bring in contact with them pieces of red 
and blue Ktmus paper. Be sure the paper is pressed well 
against the soil and allow it to remain so for several minutes. 
Then remove it and examine for any change of color. The 
soil may show the presence of either acid or base and, per- 
haps, it is neutral showing no color change at all. 

Old soils are acid and in order to grow good crops this 
condition must be corrected. Particularly is this true for 
leguminous plants such as beans, clover and alfalfa. 

4. Correcting Soil Acidity. — ^Take a basin full of acid soil 
and add to it 15 to 25 grams of burned lime. Stir the mix- 
ture thoroughly and moisten with water. Now test for 
acidity and if the soil is still acid continue to add lime fol- 
lowed by thorough mixing until the blue Htmus will not 
turn red and red Ktmus will just barely turn blue. The 
soil has now been "sweetened" as the farmer says. 



A Century of Agricultural Progress 241 

Many tons of lime are used each year to destroy the add 
condition of old soils. 

Repeat the above experiment, substituting wood ashes 
for lime. Not only will wood ashes correct the acid condi- 
tion but they give to the soil the element potassium, one 
of the three essential constituents of commercial ferti- 
lizers. 

To show the alkaline character of wood ashes shake some 
with water and allow the sediment to settle. Test the clear 
liquid with red and blue Htmus paper. This is a weak solu- 
tion of lye, and strong lye was formerly used on the farm to 
heat with fat scraps in the making of soft soap. 

5. Testing the Quality of Lime. — Place about 40 or 50 
grams of burned lime in a small basin and moisten it well 
with water. Warm the mixture a very little. If the lime 
is fresh the mass will expand and get hot, giving off steam. 
This process is called slaking, and fresh lime slakes readily. 
Place some of the slaked lime in a bottle and fill half full 
of water. Shake thoroughly and allow the mixture to 
stand for several hours. Pour off the clear Kquid and blow 
into it through a glass tube or straw. The carbon dioxide 
in your breath will turn it white because of the slaked lime 
dissolved in the water. If this does not happen, then the 
lime did not slake well. 

Place a very little of the lime in a test tube, add 10 cubic 
centimeters of water and then hydrochloric acid, a few drops 
at a time as long as the lime continues to dissolve. If the 
lime is of high purity, there will be but very Httle insoluble 
residue. 

6. Nitrogen in Soil. — Mix a little soil with an equal 
bulk of soda-lime and place the mixture in a test tube. 
Fit the test tube with a one-holed stopper and a bent de- 
livery tube dipping beneath the surface of water in another 



242 The Boys^ Own Book of Great Inventions 

test tube. Heat the mixture in a Bunsen flame 5 to 10 
minutes and test the water with red litmus paper. If it 
turns blue, nitrogen is present, the nitrogen having formed 
ammonia and dissolved in the water. 

7. Nitrogen in Organic Compounds. — Mix a small quan- 
tity of dry clover, peas or meat with soda-Kme and repeat 
the above experiment. The test will show ammonia. 

8. To Detect Renovated Butter and Olemargarine. — Melt a 
little of the sample in an iron spoon. Pure butter will melt 
quietly and produce much foam. Renovated butter and 
oleomargarine bump and sputter and will produce but 
little foam. 

9. To Test for Formaldehyde in Milk. — In the bottom of 
a test tube place a half-inch layer of concentrated sul- 
phuric acid and add one drop of a dilute solution of ferric 
cholride. Now incline the test tube and pour down the 
side some of the milk to be tested. If formaldehyde is 
present at the juncture of the two layers a purplish ring will 
be formed. 

To show the delicacy of this test add one drop of a 5 per 
cent solution of formaldehyde to a pint of nailk, stir well 
and make the test. 

10. Hard and Soft Water. — Make a soap solution by 
dissolving 2 grams of castile soap shavings in 250 cubic 
centimeters of denatured alcohol. Then add 60 cubic 
centimeters of water; if the solution is not clear, filter by 
means of a folded filter paper and fimnel. Preserve in a 
tightly stoppered bottle. 

Now to a test tube two-thirds full of water add a few 
drops of the soap solution and shake. If a cloudiness occurs 
and soapsuds do not form at once the water is hard. Con- 
tinue to add the solution, a few drops at a time, with shak- 
ing until permanent suds form. The degree of hardness 



A Century of Agricultural Progress 243 

may be judged by the quantity of soap solution that must 
be used to soften the water. 

Repeat, using distilled water or rain water. The precipi- 
tate that forms with soap in hard water is insoluble lime 
soap and until all the lime has been precipitated the cleans- 
ing action of tlie soap cannot become effective. 



Chapter XIV 
TWO CENTURIES OF ELECTRICITY 

For two centuries the word electricity has carried with 
it more of fascination and mystery than any other word in 
the language. So intangible and elusive, so subtle and 
immaterial, and yet so powerful and far-reaching in its 
effects, electricity like gravitation must be accepted but 
cannot be explained. Unable to understand its origin and 
nature, it is nevertheless possible to determine the laws that 
govern it and to harness this remarkable manifestation of 
energy to the performance of the world's work. Each dec- 
ade has seen our knowledge of it broaden and its uses 
multiply. So marvelous and varied have been its appHca- 
tions that to the popular mind nothing seems too wonder- 
ful for belief, if only the word "electrical" can be given in 
explanation. In recent years one triumph has followed 
another in such rapid succession that electricity has seemed 
at last to furnish the long sought key to the realm of magic. 
It Ughts our streets and homes, rings our door bells, runs 
our street cars, operates the machinery of our factories, 
sends our messages both by wire and ether, liberates the 
metals from the minerals of the earth, produces the hottest 
form of furnace, picks up tons of iron and steel, produces 
the X-ray and performs a multitude of household tasks 
that have made life richer and happier and this world a 
better place in which to live. 

It was in 1681 that Otto von Guericke invented the first 
electrical machine for producing electricity by friction and 

244 



Two Centuries of Electricity 245 

a little later Stephen Gray in England made the important 
discovery that certain substances are conductors and others 
insulators. Almost at the same time Cisternay Du Fay of 
France discovered that electric charges are of two kinds 
which he called ''vitreous" and ''resinous" but which 
Franklin later designated as "positive" and negative." 
These discoveries and others which followed aroused great 
popular interest and numerous experimenters were set to 
work. Demonstrations with the new found "virtue" be- 
came the order of the day. With powerful friction machines 
heavy charges were developed and great spectacular dis- 
plays were made. At a lecture before the Academy of 
Sciences in Berlin in 1744 one demonstrator succeeded in 
igniting ether by means of an electric spark, and a little 
later gunpowder was exploded in a similar manner. On 
one occasion at a dinner party given by Bose, the host 
insulated the legs of the table by placing them on pieces of 
pitch and connected the table with an electrical machine 
concealed in another room. As his guests were about to be 
seated, at a signal from Bose, the machine was started 
and to the amazement of the party "flames of fire shot from 
flowers, dishes and viands giving a most startling but 
beautiful display. " To add to the brilliant electrical effects 
the host introduced a very charming young woman, also in- 
sulated from the floor and mysteriously connected with the 
electrical machine. As each guest touched her finger tips, 
he received a shock that "made him reel. " Demonstrators 
and the public alike were alive with excitement. The world 
seemed on the verge of a new era and indeed it was. Up to 
that time, however, electricity had been little more than a 
plaything. No practical use had been made of it nor was 
there destined to be for nearly a century. 
The next great discovery showed that electric charges 



246 The Boys^ Own Book of Great Inventions 

could be stored. It was made by the Dutchman, Pieter 
Van Musschenbroeck and a German Von Kleist, working 
independently of each other. Pieter Van Musschenbroeck 
was a famous teacher of Leyden and the modern condenser 
taking its name from the ancient Dutch town was perfected 
by him and given to the public. The invention gave a new 
impetus to electrical pursuits and added much to the ex- 
perimental possibilities of the subject. 

The story of Franklin and his kite is too well known to 
need repeating here but just to keep the record straight let 
us note that this bold scientist at the risk of his life drew the 
lightning from the thunder clouds and proved its iden- 
tity with the electricity of the Leyden jar. By connecting 
the key at the end of his kite string with the knob of the 
jar he could charge the jar as readily as with the electric 
machine. 

Experiments 

I. — Rub a warm, dry glass rod with a piece of silk and 
hold it over bits of paper, cork filings, pith balls, etc. Do 
the same, substituting for the glass rod a stick of sealing 
wax, a hard rubber comb or a rod of ebony and for the silk 
a piece of flannel. 

2. — Make a wire stirup. Suspend it by a silk thread from 
a hook and place in the stirup the electrified glass rod. 
Now bring near one end of the rod an electrified rod of seal- 
ing wax or a rubber comb. Note that the two rods attract 
each other and that the suspended glass rod will follow the 
other about a circle. 

Electrify another glass rod and bring it near one end of 
the suspended rod. This time, however, the rods repel 
each other. 



Two Centuries of Electricity 247 

Repeat the above experiments placing an electrified rod 
of sealing wax in the stirup and presenting to it, first an 
electrified glass rod and then an electrified rod of sealing 
wax. 

From these experiments it will be seen that like kinds of 
electrification repel each other and unlike kinds attract. 
The charge on the glass rod is called positive and that on 
the sealing wax negative. 

3. — Make a pith-hall electroscope by bending a piece of 
heavy wire so as to make a hook at the top and insert the 
bottom in a large cork stopper to serve as base. By means 
of a silk thread suspend a pith ball from the hook. Now 
bring an electrified rod near the pith ball and it will be 
attracted to the rod, remaining in contact for a moment 
and then flying away. Do your best and for several mo- 
ments you cannot bring the rod and pith ball in contact. 
The latter will resist all your efforts and fly about in a most 
baffling maimer. Explain. 

The pith for such experiments may be obtained from 
young elder shoots and when dry is easily carved with a 
sharp knife into any shape. 

4. — On a cold winter's evening warm a sheet of paper be- 
fore the fiire and then rub it briskly for a few moments with 
your coat-sleeve or a piece of fur. Now place it against the 
wall and it will adhere for several seconds. 

5. — ^Also on a similar winter's evening try this experi- 
ment. Rub your hands briskly together and then with 
one finger extended touch Kghtly the fur of the house cat 
as she reclines on the rug before the fire. You will observe 
the fur start and the cat give a twitch as though she had 
received a shock. A small electric spark leaps between 
your finger and the cat. 

On a frosty night in an unlighted room briskly stroke the 



248 The Boys^ Own Book of Great Inventions 

back of a cat and an electrical display accompanied by 
crackling sparks will follow. 

6. — In the winter when the air is crisp and dry shuffle 
the feet briskly over a wool rug for a few seconds and then 
present one finger to a lamp fixture, a gas pipe or a radiator 
when a spark will leap across the gap. A gas jet may even 
be Kghted in this way. 

7. — ^A very simple electric machine called an electrophorus 
may easily be made and with, it a good sized electric spark 
obtained. Buy a couple of pie tins about ten inches in 
diameter and pour into one of them a melted mixture of 
equal parts of brown resin and gum shellac. Or the resin 
and shellac may be placed directly in the tin and melted 
and mixed over a small fire. Allow the mixture to cool. 
Then warm the end of a short stick of sealing wax and press 
it firmly against the center of the other tin. This makes an 
insulating handle. The outfit is completed by providing a 
square of flannel with which to rub the m^ixture of resin and 
shellac. 

To work the electrophorus, rub the mixture briskly and 
then having warmed the cover tin take it by the handle and 
place it on the mixture but do not let any part of the metal 
of the two tins come in contact. Now touch the surface of 
the cover tin with the finger. Then, first removing your 
finger lift the tin with the insulating handle and present it 
to the end of your nose or the knuckle of your other hand 
when a spark will jump between the two and you will ex- 
perience a slight shock. 

In this case the upper tin has been charged by induction. 
The mixture in the bottom tin has a negative charge gen- 
erated on it by rubbing with the flannel. When the cover 
tin is placed upon this, touching the mixture at only a few 
points of contact, positive electricity is held boimd on the 



Two Centuries of Electricity 249 

under side of the tin and negative electricity is repelled to 
the upper side. Now when the finger is placed on the cover 
tin the negative charge is repelled into the body of the ex- 
perimenter but the positive charge is held on the tin and 
when removed distributes itself over the surface. 

This principle of induction is the basis of one very im- 
portant type of static machine. 

8. — The construction of the Ley den Jar is described under 
wireless telegraphy and we will simply add here that a 
fruit jar may be used for the glass insulator and a large flat 
cork for the top. The tinfoil coatings may be made to 
adhere to the glass with shellac. A brass rod passing 
through the cork and carrying a brass chain or copper wire 
reaching to the inner tinfoil will serve for knob and con- 
nector. 

Now a Leyden jar may be charged by holding the jar in 
the hand or connecting the inner tinfoil with the earth and 
repeatedly bringing in contact with the knob the charged 
disk of an electrophorus. 

To discharge the jar, bend a piece of wire in the form of a 
half circle and to the middle of it attach a small piece of 
glass tubing for an insulating handle. Then placing one end 
of the wire in contact with the outer coating of the jar bring 
the other end near to the knob and a brilliant spark will 
jump across the gap. This is the same sort of a discharge 
that produces wireless waves, and in wireless telegraphy the 
Leyden jar has important uses. 

9. — By means of the discharger pass a spark from a 
charged Leyden jar through a gas jet and the gas will be 
ignited. 

10. — In a darkened room hold a charged Leyden jar in 
one hand and with the other bring near to the knob an in- 
candescent lamp bulb. A brilliant glow will fill the bulb 



250 The Boys' Own Book of Great Inventions 

as the discharge passes through the highly rarefied gas that 
it contains. 

II. — A frictional static machine Hke that shown in Fig. 81 
may be made as follows: Secure a board 2 feet long and 9 
inches wide for a base. At the glazier's get a glass disk 




Fig. 81. — A static machine. 



about 12 inches in diameter and have a quarter-inch hole 
ground in the center. Between two uprights, mount the 
disk on a brass rod bent at one end to provide a handle. 
At one end of the wooden base fasten a good sized cork and 
over this fit a piece of large glass tubing or a lamp chimney. 
To the top of the chimney fasten a rubbing attachment 
made of two sticks of wood covered with silk. The fric- 
tional qualities may be improved by rubbing lard on the 
silk and then coating it with an amalgam made by dissolv- 
ing a little zinc dust and metallic tin in a cubic centimeter 
of mercury. At the opposite side of the disk mount in 
similar manner a wooden cylinder covered with tinfoil and 
carrying in one end a metallic fork made of heavy wire and 
having small pointed projections fastened to each prong. 
For these projections short pieces of wire may be sharpened 
at one end and the other wound about the prong. 



Two Centuries of Electricity 251 

The silk rubbing device should be connected by a wire to 
a gas or water pipe or some other ground. 

As the machine is operated the glass disk becomes posi- 
tively charged and the pointed combs on the prongs of the 
fork take off the charge which is repelled to the opposite 
end of the tinfoil-covered cylinder. A Leyden jar may be 
quickly charged by connecting the knob with this cylinder 
and numerous experiments with static electricity performed. 

FURTHER DEVELOPMENTS IN ELECTRICITY 

For half a century after the invention of the Leyden jar 
no new electrical discovery was made and then came Gal- 
vani and Volta, pioneers in the field of current electricity. 
Up to this time the continuous flow of an electric current 
along a metallic conductor was imknown. Static electric- 
ity is essentially electricity at rest with momentary dis- 
charges of great briUiancy, but the production of a constant 
difference of potential and a uniform flow of current was 
impossible. 

In 1 79 1 Luigi Galvani, an Italian physician, was ex- 
perimenting with static electricity to learn its effects on the 
nerves and muscles of the body. Using a dissected frog for 
the experiment, he touched the nerve of the thigh lightly 
with the point of a knife and at the same time drew a spark 
from the static machine. Immediately the muscles of the 
frog began to twitch violently. Galvani continued to 
experiment with frogs' legs for years. One day he had 
several frogs hanging on an iron railing with brass hooks 
passing through their spinal cords. In his efforts to re- 
produce the twitching of the muscles he pressed the brass 
hooks against the iron railing and the muscles responded at 
once. Although he did not know it, he had produced an 



252 - The Boys^ Own Book of Great Inventions 

electric cell and a current had flowed through the nerves of 
the frog, causing the muscles to contract. 

Alexander Volta became much interested in these ex- 
periments and made a report of Galvani's great discovery 
to the Royal Society of London. Very shortly he began 
experimenting himself and to him we owe the first electric 
battery, or ''Voltaic pile, " as it was called. He foimd that 
copper and zinc placed in sulphuric acid or a solution of 
common salt and connected in external circuit would 
generate a continuous electric current. His first battery 
consisted of alternate pairs of copper and zinc disks sepa- 
rated by moistened pieces of porous paper. Volta did not 
understand the chemical action of his battery but to him 
we owe the discovery of current electricity, and the volt, 
the unit of electrical pressure, has been named in his honor. 

THE CONSTRUCTION OF CELLS 

I. — ^An acid cell can be made from a tumbler, some sul- 
phuric acid, a strip of copper and a strip of zinc. Fill the 
tumbler about two-thirds full of water and pour into it 
very slowly and with constant stirring about one-tenth that 
volume of concentrated sulphuric acid. Polish off the ends 
of the copper and zinc with sand paper and attach a two 
foot length of copper wire to each. Place these in the acid, 
but do not let them touch. 

Bubbles will rise around the zinc strip with the wires 
separated, but look closely about the copper to see if you 
can detect bubbles. Now bring the wires in contact and 
observe the copper strip. A sheath of bubbles immediately 
envelops the strip but will disappear on breaking the circuit. 

The bubbles first appearing on the zinc strip are due to 
impurities, principally carbon, in the zinc, and constitute 
what is called ''local action." Between each little impurity 



Two Centuries of Electricity 253 

and an adjacent particle of zinc an electric current is set up. 
This combination makes a miniature battery, and there are 
myriads of them over the surface of the zinc with the result 
that the zinc wastes away even on open circuit. This can 
be remedied by using chemically pure zinc or by amalgamat- 
ing the impure zinc with mercury. To amalgate it, remove 
the zinc from the tumbler and dip it into a Httle mercury. 
By rubbing, the mercury can be made to spread over the 
entire surface and cover up the impurities. 

When the copper and zinc strips are connected in external 
circuit the zinc goes into solution in the acid, liberating 
hydrogen, which is driven over to the copper strip where it 
gives up positive electricity to the copper and bubbles off. 
When the zinc goes into solution in the acid it carries away 
with it in the form of Httle positively charged particles of 
zinc, called ions, positive electricity and therefore an ex- 
cess of negative electricity, is left on the zinc strip. Thus 
the copper comes to be charged positively and the zinc 
negatively. 

This difference of charge is called difference of potential 
and is measured in volts. Difference of potential is differ- 
ence of electrical pressure and is exactly similar to differ- 
ence of water pressure. Just as water will flow from one 
level to a lower level, or from higher pressure to lower 
pressure, so electricity will flow along a copper wire from 
the positive pole to the negative pole. And just as long 
as this difference of potential is maintained the current will 
flow, i. e., as long as the acid and zinc remain or until one 
of them is used up. 

The copper is unacted upon by the acid and in this we 
have the fundamental condition for an electric cell — two 
dissimilar substances immersed in a solution which will act 
upon one and not upon the other, or that will act upon one 



254 The Boys^ Own Book of Great Inventions 

more rapidly than upon the other. The solution is called the 
electrolyte. 

Touch the ends of the wire to the tongue and describe the 
result. 

Make another cell and join the two in series by connect- 
ing the zinc of one to the copper of the other. These will 
give twice the voltage of one cell alone. Now try the effect 
of the combination on a door bell or a small buzzer. When 
not in use remove the zinc strips from the acid. 

2. The Sal Ammoniac Cell. — Secure a pint fruit jar 
with a wide mouth and fill it about one-eighth full of sal 
ammoniac which can be bought at any electrical store. Fill 
the jar to within an inch of the top with water and dissolve 
the sal ammoniac by stirring. Remove the carbon from an 
old dry cell and secure a zinc rod of the same length having 
a binding post if possible. When the carbon and zinc are 
placed in the jar and joined in external circuit a fairly strong 
current can be obtained for a short time. But this cell will 
polarize rapidly, that is, bubbles of hydrogen will gather on 
th-e positive carbon and this almost destroys the action of 
the cell. This condition may be remedied by dipping the 
rod in dilute nitric acid occasionally and then heating in a 
Bimsen flame. 

3. The Bichromt+ Cell is the best to make for home 
laboratory work, in a quart fruit jar place 710 cubic 
centimeters (about a pint and a half) of water and dissolve 
in it 80 grams (4 oz.) of chromic acid. Then add slowly 
with constant stirring 45 cubic centimeters of concentrated 
sulphiiric acid. In this place a heavy zinc strip and a car- 
bon rod provided with binding posts. The larger the sur- 
faces of the zinc and carbon the less will be the resistance 
of the cell and the more current it will deliver. Long flat 
strips about 2 inches wide and \ inch thick are best. The 



Two Centuries of Electricity 



255 



chromic acid tends to prevent polarization by oxidizing the 
hydrogen appearing at the carbon electrode. The voltage of 
this cell is high being about 2.1 volts. Ten of these cells 
grouped in series will be more than sufficient for most lab- 
oratory experiments. 

When not in use the zincs must be removed or they will 
soon be eaten away and this action also destroys the acid. 



jl9-^ 




Fig. 82. — A gravity cell and a simple form of electrode holders. 

4. — For constant circuit work such as telegraph work 
none of the above cells is suitable because of polarization. 
For this purpose the gravity cell is best suited. Secure a 
battery jar holding about a quart and a half. In this place 
a sheet of copper about 4 inches wide and 5 inches high 
having a copper wire soldered to the upper edge. Over the 



256 The Boys^ Own Book of Great Inventions 

edge of the jar hang a heavy strip of zinc bent as shown in 
Fig. 82 and carrying a binding post. Fill to within a half 
inch of the top with water to which a few drops of sulphuric 
acid have been added and drop into the bottom a small 
handful of crystals of blue vitriol or copper sulphate. 
Place the cell on short circuit and it will soon be ready for 
use. 

Although this cell does not yield a large current, its cur- 
rent and voltage are constant and the cell should be kept on 
closed circuit. As the copper sulphate is used up add more 
crystals from time to time. It will be interesting to note 
the increase in size and weight of the copper sheet as the 
cell is used. 

In any of the above cells holders for the metal or carbon 
rods may be made from two strips of wood. Cut holes in 
the ends and clamp then together with short bolts and nuts. 

SOME EFFECTS OF THE ELECTRIC CURRENT 

Europe again waxed enthusiastic over the discoveries of 
Galvanni and Volta. A v/hole new realm of experimental 
research had been opened up. Everywhere men were 
eagerly seeking to discover what this new ''galvanic in- 
fluence" might be and what other secrets the electric bat- 
tery had to reveal. One of the earliest and most distin- 
guished investigators in the new field was Sir Humphrey 
Davy. Davy was the professor of Chemistry in the Royal 
Institution of London and already famous because of his 
invention of the miner's safety lamp. His first great con- 
tribution was to explain the chemical action in Volta's cell 
and to prove that one of the two metals must be acted upon 
by the acid, or other solution, more rapidly than the other 
if a current is to be produced. 



Two Centuries of Electricity 257 

About this time two Englishmen, Messrs. Nicholson and 
CarKsle, made the important discovery that the electric 
current was able to produce chemical changes, and on 
May 7, 1800, these experimenters succeeded in decomposing 
water into hydrogen and oxygen. Here were the beginnings 
of electro-chemistry and the important commercial proc- 
esses that have developed from it. 

Davy was quick to see the possibiHties of the electric 
current in the field of chemistry and immediately began to 
investigate. In a series of brilhant experiments, now classic, 
Davy separated the alkaH metals, sodium and potassium, 
from their compounds and then quickly followed this with 
the metals, calcium, strontium and magnesium. He did 
this by passing a very heavy current through compounds of 
these metals in the melted state and thereby developed an 
electro-chemical process employed a century later at 
Niagara Falls and throughout the world. 

In this work Davy discovered the powerful heating 
effects of the current and at once began to investigate them 
further. For this purpose he made an immense battery of 
two thousand cells and passed the current from it through 
pieces of ^'charcoal about an inch long and one-sixth of an 
inch in diameter.'' Davy says that when these ^'were 
brought near each other (within the thirtieth or fortieth of 
an inch), a bright spark was produced and more than half 
of the volume became ignited to whiteness." By drawing 
the pieces of charcoal apart he was able to produce an arc 
of dazzling brilHancy four inches long. In this arc the most 
refractory substances such as platinum, quartz, sapphire, 
magnesia and lime readily melted or sublimed. Diamond 
and charcoal vaporized. In 18 10 Davy performed this 
demonstration before the members of the Royal Institution. 
Here we have the first arc light and the electric furnace, but 



258 The Boys^ Own Book of Great Inventions 

their great applications had to wait for Faraday and the 
dynamo. Batteries were too expensive and wore out too 
rapidly for such heavy currents. We cannot help but ad- 
mire Davy and the pioneer work that he did. He was one 
of the foundation builders of modern science and judged by 
the high standards of to-day his work was par excellence. 
Early in the last century, at the same time that Davy 
was carrying on his great researches, Luigi BruguateUi in 
Italy was inventing the process of electroplating. From 
this discovery have grown all modern methods of electro- 
plating and the highly important commercial process for 
the electrolytic refining of metals. So, too, has the pro- 
cess of electrotyping by which books and photographs 
are put into permanent form for printing. 

A FEW EXPERIMENTS ON THE HEATING AND CHEMICAL 
EFFECTS OF THE CURRENT 

I. — For a large number of electrical experiments a 
rheostat for reducing the current will be necessary, and as it 
will also illustrate the heating effects of the current its 
construction will be given first. 

As shown in Fig. ^2> ^^ ^ wooden base 15 inches long and 
6 inches wide mount two end pieces 4 inches square and 
between these a wooden cylinder 1 2 inches long and 3 inches 
in diameter wrapped in heavy asbestos paper. Into the 
top of one of the end pieces screw a binding post. Secure 
210 feet of bare No. 26 German silver wire and fastening 
one end to the binding post wind this upon the cylinder 
just as closely as possible without allowing the adjacent 
turns to touch. Make the other end of the wire secure to 
the opposite end-piece. Through holes bored in the end- 
pieces pass a brass rod and on this mount a sliding contact 




Fig. S^. — A rheostat. 



Two Centuries of Electricity 259 

carrying a binding post. This may be a strip of brass bent 
to shape and having two holes to permit of slipping over 
the rod. In the absence of a binding post a wire clip 
will do. 

Now connect this rheostat in series with a half dozen dry 
cells, or bichromate cells if you have them, and vary the 
resistance by moving the 

sHding contact along the p i ^ 1 ^ 

rod. When only a few 
turns of wdre are in, 
note the amount of heat 
developed and then how 
this diminishes as more 
turns are added. 

If house current is 
available connect your 
rheostat with it, but in doing so be sure that all the resist- 
ance is in when you start. Then gradually cut the resistance 
out but do not cut it all out, or you will blow a fuse. The 
blowing of the fuse depends upon the heating effect of the 
current, for when the heat reaches a certain amount the 
fuse wire melts and breaks the circuit, thus protecting the 
lamps from an excessive current. 

2. — Connect your rheostat and a two-foot length of No. 
30 iron wire in series with the house current and gradually 
cut out the resistance. The wire will become incandescent 
and begin to burn. If house current is unavailable use a 
shorter piece of wire and six dry cells. 

3. — Cover a board 4 inches wide and 6 inches long with 
asbestos and screw into each end a binding post. Between 
the binding posts connect a piece of No. 30 iron wire, allow- 
ing it to touch the board. Upon this place a Uttle heap of 
gunpowder and by means of long wires connect the board 



26o The Boys^ Own Book of Great Inventions 



with six or eight dry cells. The heat developed will ignite 
the powder. 

A pair of wires with wire clips attached to their ends will 
be found very convenient for making quick connections. 
4. — Between the binding posts of the board in experi- 
ment 3 place wires of different materials and with each 
material use wires of varying diameter. Also in each case 
by means of the rheostat vary the amount of current used, 
In this way you will learn how the kind 
of material and its size and the quantity 
of current used affect the amount of 
heat developed. 

5. — ^Wind a length of No. 26 German 
silver wire about a lead pencil so as to 
form a spiral and when it has set re- 
move and immerse in a tumbler or can 
of water. Connect the ends of the loop 
with 8 dry cells or in series with the 
rheostat and the house current. The 
heat developed will cause the water to 
boil. Electric hot point heating irons 
are made in this way. 

6. — Secure two electric light car- 
bons and fasten to one end of each a 
Fig. 84.— The electric ]^eavy copper wire. Moimt these car- 
bons in a vertical position on a ring 
stand by means of clamps as shown in Fig. 84 and insul- 
ate the carbons from the clamps with asbestos paper. 
Now connect the carbons in series with the rheostat and 
the house current, having the resistance all in at the start. 
Bring the carbons together lightly and gradually cut out 
the resistance until the ends begin to glow. Draw the car- 
bons apart slightly and cut out more resistance. Draw 




Two Centuries of Electricity 



261 



them still further apart and if necessary cut out additional 
resistance. An arc of dazzling brilliancy will be formed 
and in it you can put pieces of various metals, lime, 
quartz, etc. These may be held in the arc by means of 
iron tongs. This is the sort of an arc that Davy produced. 



m> 



~\ 




-RUBBER COVERED 
WIRE 



Fig. 85. — Electrolysis apparatus. 

This experiment should not be done, however, without 
colored glasses. 

7. Electrolysis of Water. — ^Arrange a battery jar, ring 
stand, clamps and two large test tubes as shown in Fig. 85. 
Two pieces of platinum foil will be necessary for this experi- 
ment, but they may be small. Make a tiny hole in each 
foil and through it draw a copper wire, bending the end over. 



262 The Boys^ Own Book of Great Inventions 

Arrange these as shown in the figure. The wire must be 
rubber covered in order to insulate it. 

Make a solution of sulphuric acid and water having about 
one part of acid to twenty parts of water. Always pour 
the acid into the water. Have the jar about three-fourths 
full of the solution and invert over the platinum electrodes, 
test tubes filled with the same and make secure with the 
clamps. 

Connect the wires from the platinimi electrodes with 6 
dry cells and allow the action to continue until one of the 
platinums is nearly exposed. Remove the test tube having 
the larger volume of gas and keeping the mouth down apply 
a lighted match to it. This is hydrogen. Loosen the clamp 
from the other test tube and placing the thumb over its 
mouth remove it. With the mouth up insert a glowing 
splint into the gas and it will be kindled into a flame. This 
is oxygen. 

This experiment may be performed with copper elec- 
trodes, but only hydrogen will be obtained for the oxygen 
will unite with the copper. 

8. — Repeat the above experiment using a solution of 
sodium sulphate instead of sulphuric acid and color this 
with a solution of blue litmus. Upon passing the current 
the solution in the hydrogen test tube will remain a deep 
blue, but in the oxygen test tube it will turn red. When the 
colors have appeared reverse the connections and the colors 
will also reverse. Acid is formed in the red test tube and 
base in the blue. 

9. Copper Plating. — In an oblong battery jar about 10 
inches long and 5 inches square on the end as shown in Fig. 
86, place a saturated solution of copper sulphate. To pre- 
pare the solution crush the crystals and stir them with 
water allowing the mixture to stand overnight. Across 



Two Centuries of Electricity 



263 




Fig. 86. — Copper plating bath. 



the ends of the jar place small pieces of wood carrying bind- 
ing posts or simply place a heavy bent wire across. To one 
terminal attach a piece of heavy sheet copper about two 
inches square and to the 
other terminal a door 
key or some other object 
which you wish to plate. 
This object must be pol- 
ished with rouge cloth 
first so as to free it from 
dirt and grease. 

For the source of cur- 
rent either three gravity 
cells or two storage cells 
connected in series are 
best. 

The positive pole should be connected to the sheet of 
copper and the negative pole to the object to be plated. 
In a short time a bright, firm deposit of copper will be made. 

Just as fast as copper is driven out of solution on to the 
object to be plated more copper is brought into solution 
from the copper sheet which wastes away and must be 
replaced from time to time. If the deposit is slow in form- 
ing, bring the electrodes closer together. 

10. Nickel Plating. — ^An object to be nickeled is usually 
copper plated first. For this experiment use an electric 
light carbon and to get the coat of copper place it at the 
negative pole of the copper plating bath for a few minutes. 
Remove and poHsh with rouge cloth. 

Now prepare a nickel plating bath by dissolving in one 
Hter of water (about one quart) 72 grams of nickel ammo- 
nium sulphate, 23 grams of ammonium sulphate and 5 
grams of crystiHzed citric acid. A gram is about one-seventh 



264 The Boys^ Own Book of Great Inventions 

of an ounce. Now add household ammonia to this solu- 
tion slowly and with stirring until it will only just barely 
turn blue Utmus paper red, but do not add more than this 
amount. The solution must be left acid. 

Arrange the nickel plating bath the same as for copper 
plating, placing the copper covered carbon at the negative 
pole and a strip of nickel at the positive pole. Connect 
with three gravity cells or two storage cells as before and 
allow the current to flow until a good deposit has been 
made. Remove and polish with rouge cloth. In this ex- 
periment a smaller jar may be used and the plate and carbon 
placed closer together. 

II. Electrotjrping.— Where a large mmiber of copies of 
any pubHcation are to be printed the soft type metal is 
not durable enough to give clean-cut impressions. There- 
fore a wax impression of the type is obtained and electro- 
types are made. 

Upon a strip of sheet lead 6 inches long and i^ inches 
wide place pieces of beeswax and melt them over a small 
Bunsen flame. Allow the melted beeswax to run evenly 
over the sheet of lead forming a layer ^ of an inch thick. 

When the wax is hard rub it over thoroughly with pow- 
dered graphite, using a soft cloth. Dust the object you wish 
to electrotype with graphite and press it into the wax until 
a clean-cut impression is made. Now dust this impression 
again with graphite and rub to a smooth shiny surface. 
Attach a wire to a hole in the top of the lead strip and be 
sure the graphite extends onto the lead so as to make a con- 
tinuous conducting surface. 

Place the lead strip at the negative pole of the copper 
plating bath and allow the current from two gravity cells 
or one storage cell to run for 24 hours. At the end of this 
time remove the lead strip, wipe it dry, soften the beeswax 



Two Centuries of Electricity 265 

over the flame and strip off the thin deposit of copper. 
If desired, back it with melted tin. 



ELECTRO-MAGNETISM 

A discovery of the first importance was made by Hans 
Christian Oersted, a Danish physicist, in the year 18 19. 
One day as he was lecturing before his class it occurred to 
him to place a wire carrying an electric current over a 
compass needle and parallel to it. To his surprise the needle 
turned and set itself in a nearly east and west direction at 
right angles to the wire. When he reversed the current 
he found that the needle was deflected in the opposite 
direction. For the first time positive proof had been given 
of the very close relationship between magnetism and 
electricity. Many had suspected it, but no one before had 
been able to demonstrate the fact. When a Httle later it 
was also shown that a coil of wire through which an electric 
current is flowing, itself, possesses a magnetic field the basis 
was laid for a new realm of electrical research. 

It is hard for us to understand in these days of marvelous 
achievement the very great interest these early discoveries 
made throughout Europe. But simple as these facts now 
seem and famihar as they are to every schoolboy they are 
the great epoch-making discoveries without which later 
progress would have been impossible. 

In the year following Oersted's great discovery a French- 
man, Andre Marie Ampere, found that a coil of wire through 
which a current flows acts Hke a magnet and will attract 
or repel a similar coil according to the relative directions 
of the current in the two coils. If the current in the coils 
flows in the same direction there is attraction and if in the 
opposite direction repulsion. 



266 The Boys' Own Book of Great Inventions 

In this same year Arago, another Frenchman, whirled a 
copper disk placed in a horizontal plane beneath a suspended 
compass needle and found that the needle would whirl too. 
It remained for Faraday to explain this action a number of 
years later, but here is the first instance of induced currents, 
the basis of present day commercial electricity. 

In 1824 Sturgeon made the first electro-magnet. He 
wound a munber of turns of insulated copper wire upon a 
soft iron core and found that its attraction for other pieces 
of iron was very great. Joseph Henry, the pioneer worker 
with current electricity in this country, shortly after this 
made electro-magnets of great lifting power. With one mag- 
net weighing 59I pounds he was able to Hft a ton of iron. 
A Httle later Samuel F. B. Morse, equipped with the idea 
of the electro-magnet, invented the telegraph, the first 
great commercial appHcation of electricity. Since then a 
host of applications of this simple device have been made 
and without it many of the most useful electrical inventions 
would have been impossible. In capacity the electro- 
magnets range from the deHcate relay actuated by the very 
feeble currents of long distance telegraph lines to the large 
commercial Kfting magnets capable of sustaining many 
tons of iron and steel. Lifting magnets require no grappling 
hooks. A crane lowers the magnet until it comes in con- 
tact with the mass of iron and the closing of a switch pro- 
duces millions of invisible magnetic lines of force which more 
securely than hooks of steel grapple the iron and hold it fast. 
When the mass of iron is to be released the circuit is broken 
and these mysterious Hues of force immediately disappear. 

An electro-magnet is a temporary magnet and possesses 
magnetism only so long as the current flows in it. The core 
of the magnet is soft iron having very great capacity for 
absorbing and concentrating the lines of force but instantly 




w 



Two Centuries of Electricity 



267 



losing its magnetism when the circuit is broken. A coil 
of wire without a soft iron core is called a solenoid. It 
possesses a magnetic field when a current is passed through 
it as Ampere showed, but the intensity of this field is many 
times less than it is with a soft iron core. 

A decade later Faraday was to show a still more intimate 
relation between electricity and magnetism and to lay the 
foundation for modern dynamo currents. 



EXPERIMENTS ON ELECTRO-MAGNETISM 

I. — In order to repeat Oersted^ s experiment, if you do not 
already have one, make a compass similar to the one shown 



N 



yl\ 



s 




Fig. 87. — An easily constructed compass. 

in Fig. 87. To do this secure a piece of steel watch spring 
4 or 5 inches long and after having straightened it out make 
a dent in the center with a nail punch and bend as indicated. 
To magnetize this, stroke it from the middle toward one 
end with the positive pole of a bar magnet and from the 
middle toward the opposite end with the negative pole. 
Cut a quarter-inch thickness from the end of a large cork 



268 The Boys' Own Book of Great Inventions 

and thrust the blunt end of a sewing needle into this and 
mount upon it the magnetized watch spring. If it does not 
balance trim off the ends with cutting pKers until it does. 

Now connect two dry cells in series with a two-foot length 
of copper wire and hold it over the compass needle in a north 
and south direction. Note the deflection of the needle. 
Repeat with the current flowing in the opposite direction 
and note that the deflection is also in the opposite direction. 
Kjiowing that the current flows from the positive pole to 
the negative, see if you can work out a rule for determining 
the direction of a current by means of the deflection of a 
compass needle. 

Hold the wire joining the cells in a vertical position and 
near to the compass. Note the effect on the needle. Re- 
verse the direction of the current and note the effect. 

It is upon experiments of this kind that Wheatstone's 
telegraph was based and also one type of electrical measur- 
ing instruments. 

2. Ampere's Experiment. — Make two coils about 4 
inches across of 200 feet each of No. 26 cotton-insulted 
copper wire and wind with tape to hold in position. Con- 
nect one of these coils with 6 or 8 dry cells and holding the 
coil by the two lead wires present one face of it to the north 
pole of a compass needle. Note the attraction or repulsion. 
Then turn the coil about and present its other face to the 
compass needle. 

Connect each coil with a half dozen dry cells and sus- 
pending each by the lead wires bring their faces close to- 
gether. They will either attract or repel each other. Now 
reverse one of them and observe the effect. If there was 
attraction before there will be repulsion now. 

3. Effect of Soft Iron on the Strength of a Magnet. — 
Place some iron filings or small iron nails on the table and 



Two Centuries of Electricity 269 

bring one of the coils of wire near them. Have the coil 
connected with a dozen dry cells or better in series with 
the rheostat and the house current. Note the Hf ting power. 

Now thrust through the coil and into the fiHngs a large 
soft iron bolt. Break the circuit and note how the mag- 
netism immediately disappears. Holding the end of the 
bolt about a half inch above the filings make the circuit 
and observe the effect. 

4. A Lifting Magnet. — An electro-magnet that will lift 
well above 100 pounds and which may be connected in 
safety to a no- volt lighting circuit may be made as follows: 

Go to a blacksmith shop and secure a soft iron rod about 
I inch in diameter and 4 inches long. Smooth off the ends 
and slip over the rod a piece of stock-fiber tubing followed 
at each end by a tight-fitting washer of the same material 
about three inches in diameter. Leave the ends of the rod 
uncovered as shown in the diagram. The fiber tubing and 
washers will make an excellent spool upon which to wind 
the wire. Now wind upon this spool 1,200 feet of No. 26 
double-covered copper wire. This may be wound by hand 
in a short time or a reel can be easily made to hasten the 
process. To guard against unwinding, the ends of the wire 
may be taken out through holes punched in one of the 
washers. Provide a hook for handle or for attaching to a 
system of pulleys by drilling and threading a hole in one 
end of the soft iron core into which screw a threaded hook 
of proper size. A soft iron hanger for the opposite end may 
be made in a similar way. 

The resistance of the coil of wire is such that the current 
flowing in it with 1 10 volts pressure will be about 2 amperes 
which is well under the capacity of an ordinary house fuse. 
The current should never be allowed to run for more than 
a few minutes at a time, though, as the heat developed 



270 The Boys' Own Book of Great Inventions 




Fig. 88. — A Kfting magnet. 



Two Centuries of Electricity 271 

might char the insulation and short circuit the coil. A 
simple switch to make and break the circuit may be easily 
devised. 

When complete, try its Hfting power on nails, bolts, 
spikes and other pieces of iron. To test its strength make 
a hanging platform by boring holes in each corner of a 
board 18 inches square and suspend from the hanger hook 
by ropes passed through the holes. Throw the switch and 
pile on heavy objects until the hanger with its load, becom- 
ing too great for the strength of the magnet, drops off. You 
will be surprised to discover what a Httle giant you have 
made. 

With a load of nails cHnging to the magnet break the cir- 
cuit and note the immediate loss of magnetism. You will 
understand then how valuable large commercial Ufting 
magnets are for loading steel rails, pig iron and castings 
in steel mills and foundries. No grappHng hooks are neces- 
sary, only the throwing of a switch and when the load has 
been swung into position it may be released just as easily 
and at a moment's notice by the breaking of the circuit. 
Mysterious and invisible, these magnetic lines of force may 
be called into instant action and better than hooks of steel 
they seize their load and deposit it in any desired spot. 

5. A Buzzer. — Make an electro-magnet using 100 feet 
of No. 26 cotton-covered wire in the same manner as the 
large hfting magnet in the previous experiment and mount 
it on a wooden base as shown in Fig. 89. Heat one end of a 
steel clock spring to draw the temper and drill a hole through 
it. Bend and mount as shown. In one end of the base in- 
sert a wooden post and extend from the top of it a brass 
arm carrying a contact screw. Adjust this screw imtil 
it just touches the bent spring. Connect one end of the 
magnet wire to the screw at the base of the spring and the 



272 



The Boys^ Own Book of Great Inventions 



other with a battery. Connect the other battery wire with 
the adjustment screw. 

When the circuit is made the magnet draws the spring 
away from the contact point. This breaks the circuit and 

the magnet loses its 



jUULQ^^m 




Fig. 89. — A buzzer. 



magnetism allowing the 
spring to fly back in 
contact with the screw, 
again making the cir- 
cuit. This process is 
repeated over and over. 
The working of this 
simple buzzer is ex- 
actly the same as that 
of an ordinary door 
bell. 



6. Magnetic Permeability. — Connect up the large Hft- 
ing magnet described in experiment 4 with the house cir- 
cuit and over one pole hold a six-inch square of window 
glass upon which iron filings have been placed. Make and 
break the circuit noting the very marked effect upon the 
filings. Move the glass about and observe how the filings 
tend to remain near the pole. 

Repeat the above experiment using a square of wood 
instead of glass. This fact, that lines of force will pass 
through such substances as glass and wood, is called mag- 
netic permeabiKty. 

Now substitute a thin piece of sheet iron and note the 
different effect. Why is this? 

THE STORAGE BATTERY 

Among the most important commercial applications of 
the chemical effects of the current is the modern storage 



Two Centuries of Electricity 273 

battery. As early as 1801 it was discovered by Gautherot 
that platinum wires used as electrodes in the electrolysis 
of water would send a current in the opposite direction if 
the battery were removed. A number of other men in- 
cluding Faraday experimented with secondary cells, as 
they were called, but not until Plante of France in i860 
developed the lead cell was a successful storage battery 
invented. 

While the storage battery may be charged by passing 
current into it and it seems to "accumulate" electric energy, 
there is of course no actual storing of electricity. When the 
current is passed, chemical changes take place in the elec- 
trolyte and on the plates of the battery and it is really 
chemical energy which is stored. When the charging cir- 
cuit is broken and the battery is connected in external 
circuit, a reverse set of chemical changes occur and a cur- 
rent flows from the cell in the opposite direction to the 
charging current. 

Plante's storage cell consisted of two lead plates placed 
in a solution of sulphuric acid and connected to a source of 
current. After the current had flowed for a short time one 
plate was found to be coated with lead oxide while the 
other remained unchanged. When these plates were con- 
nected in external circuit the cell was found to develop an 
electro-motive force of a little more than two volts. Later 
it was found that the capacity of the cell could be increased 
by grooving the plates and filling the grooves with a paste 
of oxides of lead. Red oxide of lead is used on the positive 
plate and Ktharge on the negative. 

While the lead storage cell has come into wide use and 
has met a large number of very real needs in a fairly satis- 
factory manner, it is not an ideal cell. It possesses a number 
of disadvantages as the users of this cell only too well know. 



274 The Boys^ Own Book of Great Inventions 

Being made of lead its weight is very great. The sulphuric 
acid must be of definite specific gravity. The cell must not 
be discharged too low, and over charging or very rapid 
charging are to be avoided. The cell cannot stand during 
periods of idleness in the discharged condition. It must be 
left charged and frequently recharged during these periods. 
In spite of the best care the plates of the lead cell will 
permanently sulphate to some extent and to just that ex- 
tent its Hfe is destroyed. Their comparatively low cost 
and high voltage, however, have made lead cells very- 
popular and with proper care they will last a long while. 

One of the most remarkable products of modern inventive 
genius is the Edison Storage Battery. After eight years of 
research and nine thousand experiments the great inventor 
gave to the world a storage battery that well deserves the 
description, ''Built like a watch: rugged as a battleship." 
It is fool proof, and after nine years of severe testing is 
apparently indestructible. It may stand charged or dis- 
charged, be discharged to zero voltage, charged in the re- 
verse direction or subjected to any treatment, however 
severe, without injury. It is Kght and easily portable. 

The Edison cell employs an electrolyte of caustic potash 
or soda instead of sulphuric acid. The positive plate is 
made up of a series of perforated metal tubes packed with 
alternate layers of very light flake nickel and nickel hydrate. 
These tubes are made of steel and electroplated with nickel. 
The negative plate consists of a series of perforated steel 
jackets nickel plated and packed with iron oxide. The 
caustic potash solution makes its way through the perfora- 
tions in the tubes and pockets coming in contact with these 
materials. On charging, the nickel hydrate changes to an 
oxide and the iron oxide is reduced to a metallic iron. 

Uses of Storage Cells. — Both lead and Edison storage 



Two Centuries of Electricity 275 

cells have many important uses. In power plants large 
batteries of storage cells are charged when the demand upon 
the dynamos is Hght and then when the demand is heavy 
these cells are placed in parallel with the dynamos to help 
carry the load. In periods of very light load the storage 
cells are frequently able to carry it alone. In times of 
accident storage cells serve as an auxihary supply to be 
switched in at a moment's notice. 

For the small electric Hght plant in rural communities 
storage cells are indispensable. They may be charged from 
a dynamo run by a gasoline engine or a small water fall. 
Much water power on farms throughout the country goes 
to waste which at comparatively small expense might be 
converted into electric energy and by means of storage cells 
made to supply an abundance of Hght and power. Such a 
storage battery plant on the farm will not only Hght the 
house and outbuildings but wiU also supply power for the 
laundry, pump water, run motors for operating milking 
machines and cream separators, feed cutters, wood miUs, 
grindstones and a score of other appHances. 

The storage battery is also extensively used to operate 
electric trucks, for train Hghting and railway signaHng, 
for miners' lamps, submarines, wireless work, yacht Hght- 
ing, automobile ignition, Hghting and self-starting service, 
laboratory work and many other uses. For driving sub- 
marines a large number of huge storage cells each having a 
capacity of 3,500 ampere-hours is employed. 

A Simple Storage Cell. — Into a tumbler two-thirds fuU of 
water pour about one-tenth of that volume of sulphuric acid 
slowly and with constant stirring. In this by means of 
wooden clamp holders suspend two strips of heavy sheet 
lead about 5 inches long and i inch wide. Connect the ceU 
with 3 dry ceUs for about five minutes. Remove the lead 



276 The Boys' Own Book of Great Inventions 

strips and observe their color and appearance. Replace 
them in the acid and connect the cell with a buzzer or elec- 
tric bell. 



FAEADAY AND INDUCED CURRENTS 

Important as battery currents were and are yet, the very 
great electrical progress of the nineteenth century and since 
would have been utterly impossible without some other 
means of generating electric pressures and currents. Even 
storage batteries were not a commercial success until dy- 
namo current was available for charging them. But Oer- 
sted, Ampere and Arago had made discoveries v/hich the 
genius of Michael Faraday used as the basis for still further 
experiment, and in a series of epoch-making discoveries in 
the year 183 1 he laid for all time the foundations of com- 
mercial electricity. 

No higher type of man can be found in all history than 
Michael Faraday. Quiet, unassuming, of childish gentle- 
ness and simpKcity, vdth. no thought of private gain and 
actuated only by an intense love of truth, he devoted his 
life in imselfish loyalty to the advancement of science. 
Had he sought financial fortune, it was within his grasp. 
Millions have been made from inventions based on his 
discoveries. Faraday's passion was not for money but 
rather adding to the sum total of human knowledge, and no 
single investigator ever added more. His researches were 
not confined to electricity but covered a wide range of sub- 
jects in both chemistry and physics. Whenever a great 
discovery had been made, he left its commercial develop- 
ment to other men and turned with renewed enthusiasm 
to a fresh field of research. So long as the pursuit of truth 
engages the interest of men, the name of Michael Faraday 



Two Centuries of Electricity 277 

will take first rank in the record of scientific achievement. 
In this day of intense commercialism and keen rivalry it is 
good to. contemplate such utter forgetfulness of self and 
complete devotion to truth for truth's sake. 

Son of a blacksmith and apprenticed to a bookbinder, 
Faraday attended four lectures by Sir Humphrey Davy 
and became so deeply interested in the new field of scientific 
discovery to which these lectures introduced him that he 
appKed to Davy for a position as laboratory assistant in 
the Royal Institution. Although discouraged by Davy 
from entering upon such a life, Faraday received the coveted 
appointment and at the age of 22 began a period of service 
for the cause of science which was to last without interrup- 
tion in the same laboratory for 46 years. 

It will be remembered that Arago had caused a compass 
needle to rotate by whirling rapidly beneath it a copper 
disk. Why this rotation should occur was a complete 
mystery to Arago and all others except Faraday, and even 
with him the solution of the problem was only a conjecture. 
He suspected that electric currents were induced in the 
copper disk and that these currents acting upon the opposite 
ends of the needle caused it to rotate. With the scientist 
all theories m.ust be subjected to experimental proof, and 
Faraday immediately set to work to verify his suppositions. 
He mounted a large copper disk so that he could whirl it 
between the poles of a powerful horseshoe magnet. Aroimd 
the axis of the disk he passed a copper Vv^ire and carried it to 
a sensitive galvanometer. The other galvanometer wire 
he held against the edge of the disk. Then as he whirled 
the disk, just as Faraday had suspected, the galvanometer 
needle was deflected, showing the presence of an electric 
current. Thus Faraday had estabhshed the fact that a 
magnetic field may be made to generate electricity. This 



278 The Boys^ Own Book of Great Inventions 

is really the converse of Oersted's discovery that a current 
bearing conductor possesses magnetic Knes of force. 

In this rotating disk of Faraday's we have the first crude 
dynamo. Not much to invent you may think, so simple 
and imperfect, so feeble in its output, and yet within it lay 
the germ of every generator of later times from the toy 
dynamo of the playroom to the huge generators at Niagara 
Falls. It is not the perfection of an intricate mechanism 
which must be recognized as a work of genius, but the dis- 
covery of the principle which underlies it. Very often the 
discovery of the principle and its application in a suitable 
machine are made by the same experimenter, but we should 
always remember that the principle must precede the 
application. 

Faraday substituted a rotating coil of wire for the copper 
disk and thus made a real dynamo but the mechanism was 
so crude and the losses in generating the current so great 
that commercial success was impossible. Faraday, however, 
had blazed the way, and later inventors simply applied with 
greater perfection of mechanical details the principle which 
he had discovered. 

Even before the experiment with the rotating disk Fara- 
day had discovered the law of induced currents. He kept 
asking himself the question— "If an electric current will 
magnetize iron, why will not a magnet produce an electric 
current?" And again by direct experimentation he sought 
an answer to his question. He connected a coil of wire to 
a sensitive galvanometer and thrust into it a strong bar 
magnet. As he did so he observed a slight throw of the 
needle. But contrary to his expectation the needle re- 
turned to its position of rest as the movement of the magnet 
ceased. He observed another throw of the needle, however, 
as he withdrew the magnet and thus discovered that a coil 



Two Centuries of Electricity 279 

of wire will have a current induced in it only when the lines 
of force which induce the current are made to cut across 
the coil. 

Faraday next set out to discover whether or not the 
magnetic field about one coil through which a current was 
flowing would induce a current in another coil near to it 
but insulated from it. To determine this he wound two 
coils of wire, one of 60 feet and the other of 72 feet, on the 
same wooden spool and insulated them from each other 
with twine string and calico cloth. One of these coils he 
connected with a galvanometer and the other with a battery 
of ten cells. As the current flowed through the coil not the 
sHghtest effect upon the needle could be observed, but when 
the circuit was broken there was the throw of the needle. 
A current was surely induced, and just at the instant that 
the circuit was made again there was another throw of the 
needle. Faraday had estabhshed the fact that the magnetic 
field of one current will induce a current in an adjacent 
coil provided this magnetic field is changing. Faraday 
observed, too, that the throw of the needle was in one direc- 
tion when the circuit was made and in the opposite direction 
when it was broken. Evidently the induced current flowed 
in opposite directions in the two cases. Here was the whole 
story of induced currents. When the circuit is made the 
lines of force surge outward from the first or primary coil 
and cut across the turns of the secondary coil, inducing a 
current in one direction. When the circuit is broken the 
lines of force surge inward again, cutting the secondary and 
inducing a current in the opposite direction. In this simple 
apparatus Faraday gave to the world the first induction 
coil and the first transformer. Wireless telegraphy, the 
long distance transmission of electric power, the telephone, 
the X-Ray and numerous other appHcations of electricity 



28o The Boys^ Oivn Book of Great Inventions 

were made possible by the perfection of these two electrical 
inventions. Both are described more fully in the chapter 
on wireless. 

Knowing the influence of soft iron on the intensity of an 
electro-magnet, Faraday substituted a soft iron ring for the 
wooden spool, winding the primary upon one half and the 
secondary upon the opposite half. The result was a very 
much stronger induced current. He made the number of 
turns on the secondary greater than on the primary and 
again increased the voltage. In one experiment he con- 
nected the terminals of the secondary to two pencils of 
charcoal resting Hghtly against each other and obtained an 
electric spark, the first discharge of an induction coil ever 
made. 

These epoch-making discoveries which laid the founda- 
tion for nearly a century of unparalleled progress were made 
by Faraday within the short space of ten days, but they had 
been preceded by nine years of experimental research. It 
is to the man who is willing to devote himself to years of 
patient research that the world owes its greatest discoveries 
and inventions. Very frequently so-called genius is simply 
another name for drudgery. 

EXPERIMENTS WITH INDUCED CURRENTS 

I. The Principle of Induction. — Wind about 500 turns 
of No. 22 insulated copper wire into a coil 2^/2 inches in 
diameter and make secure with binding tape. Connect the 
ends of the coil with a watch case telephone receiver and 
holding it to the ear thrust into the coil one pole of a strong 
bar magnet. A distinct click will be heard. Withdraw the 
magnet and a second cHck will be heard. 

Instead of the telephone receiver a galvanometer may 



Two Centuries of Electricity 281 

be made by winding into a somewhat elongated coil 100 
turns of the same wire as above. Place this in a vertical 
plane with the long axis parallel with the compass needle. 
Now suspend inside the loop a magnetized sewing needle 
by means of a silk thread. Connect the ends of the two 
coils and thrust the magnet as before. At each cutting of 
the turns of wire by the Hnes of force there will be a quick 
throw of the needle and it will be observed that the deflec- 
tions in the two cases are in opposite directions. 

2. A Minature Transformer. — On the opposite halves of 
a soft iron ring about 5 inches in diameter wind two coils. 
The primary coil should contain about 15 feet of No. 14 
insulated copper wire and the secondary 500 feet of No. 26 
wire. Connect the primary with a half dozen dry cells and 
the secondary with the telephone receiver or galvanometer. 
Now make and break the primary circuit. At each make 
and break a distinct click of the receiver or throw of the 
needle will result. This is a minature transformer. Wet 
your fingers and hold them on the terminals of the second- 
ary as the primary is made and broken. 

3. Lighting a Lamp hy Induction. — If alternating current 
is available a very interesting experiment to show the 
effects of induction can be performed. Wind into a coil 
about 4 inches in diameter i pound of No. 18 bell wire and 
cover it with tape. Connect the ends to a small 4 volt 
glow lamp. Now connect the large lifting magnet, described 
in experiment 4 under electro-magnetism, with an alternat- 
ing current of 1 10 volts and hold over one end of it the coil 
and lamp. The current induced in the coil will Hght the 
lamp. The rapid alternations of the current will have the 
same effect as the making and breaking of the circuit in the 
previous experiment. Although there is no connection 
between the two coils the lamp will light. 



282 The Boys^ Own Book of Great Inventions 

For this experiment an electro-magnet with half as many 
feet of wire would be even better. 

4. A Simple Transformer. — Transformers are of two 
kinds — " step-up '^ and "step-down." The step-up trans- 
former takes an alternating current of low voltage and 
large quantity and transforms it into a current of high 
voltage and small quantity for long distance transmission 
of electric power, while a step-down transformer performs 
the reverse operation at the other end of the Kne. 

Neglecting the small loss of energy in the transformer 
itself there are just as many watts in the primary as in the 
secondary, but the voltage in one will be low and the am- 
perage high, while in the other the opposite will be true. 
Now the watts are equal to the volts times the amperes. 
Therefore, if in the secondary of the transformer the volt- 
age is increased 10 times over what it is in the primary, the 
number of amperes must be only one-tenth as great as in 
the primary, for the product of the volts and amperes in 
each coil must be the same. The voltage in the two coils 
of a transformer will depend upon the relative numbers of 
turns of wire. If the primary has 100 turns and the second- 
ary 10,000 then a current of 100 volts pressure and 10 
amperes in the primary will be changed into a current of 
10,000 volts and ^/lo of an ampere in the secondary. It 
will be observed that the product of the volts and amperes 
in each case is the same. 

For running electric trains and small motors it is very 
convenient to be able to step down the voltage of the alter- 
nating current of the house lighting circuit to 6 or 10 volts. 
Suppose it is wanted to build a no watt transformer to 
change from no volts to 10 volts. Since our transformer 
is to have a capacity of no watts and the voltage of the 
primary circuit is no volts the number of amperes in the 



Two Centuries of Electricity 



283 



primary will be i. Therefore, looking in a wire table we 
will select a wire having a safe carrying capacity of i am- 
pere which will be about No. 26. Although Ohm's law of 
resistance does not strictly apply to alternating currents 
we will assume that it does. Since the current times the 
resistance equals the volts in order to get i ampere with 
no volts we shall need no ohms resistance. Allowing for 
the fact that this is alternating current 100 ohms will be 




Fig. 90. — A simple transformer. 

more nearly correct. Now the table shows that i foot of 
No. 26 wire has a resistance of .04 ohm. Therefore to get 
100 ohms we shall need 2,500 feet. 

For the cores upon which to wind the coils select two 
bolts each 4 inches long and join them together with soft 
iron strips. Upon each bolt place a piece of stock fiber 
tubing and at each end a tight fitting washer of the same 
material. Now wind upon one of these spools 2,500 feet of 
No. 26 double covered copper wire and count the number 
of turns. Cover every layer with a sheet of stiff writing 
paper. The ends of the wire may be passed through holes 
in the washers. 

Since the voltage of the secondary is to be ^/u that of 
the primary the number of amperes will be 11 times as 
great or in this case 11. Looking in the wire table we find 



284 The Boys^ Own Book of Great Inventions 

that No. 14 wire comes the nearest to having a safe carry- 
ing capacity of 11 amperes. Since the voltage in the pri- 
mary is 1 1 times greater than it is to be in the secondary, 
there will need to be but Vii ^^ many turns in the second- 
ary coil. Therefore, knowing the nimiber of turns on the 
primary, wind Vn of this number of turns of No. 14 wire 
on the opposite spool. The construction will become clear 
from Fig. 90. 

The secondary coil may be connected with the motor to 
be run and the primary with the house circuit. To reduce 
the voltage still further connect in series with the primary 
and motor or other apparatus a small resistance. 

DYNAMOS AND MOTORS 

It was more than thirty years after Faraday's simple 
disk dynamo had demonstrated the possibility of an in- 
duction generator before a commercial dynamo was in- 
vented. About 1865 Dr. Henry Wilde of England invented 
a separately excited dynamo which was operated by a 
steam engine and developed currents of considerable 
strength. Other experimenters immediately went to work 
and in fifteen years the present day commercial dynamo 
was well on the road to perfection. 

The parts of a dynamo will become clear from a consid- 
eration of Fig. 91. At A we have a simple alternator. The 
poles of the field magnet are at N and S. The loop ABCD 
constitutes the armature. The collecting rings and brushes 
for taking off the current are shown at the end of the shaft. 
The lines of force from the field magnet pass from N to S 
and as the armature is turned in the direction indicated by 
the arrow it is made to cut the lines of force and a current 
is induced in it. This current flows about the loop in the 



Two Centuries of Electricity 



28s 



direction shown and through the external circuit from the 
positive brush to the negative brush. When this loop has 
turned through 90 degrees from its present position, the 
sides of the loop, AB and CD, will not be cutting the lines 
of force but will be moving parallel with them and there- 
fore no current will be flowing in the loop. In the next 
instant, however, AB which has been rising through the 




Fig. 91. — The construction of the dynamo. 

lines of force will be faUing and CD which has been falling 
through the Hnes of force will be rising. Therefore at this 
point the current in the loop and also in the external circuit 
will reverse its direction. As can be seen this will happen 
twice during each revolution and therefore such a gener- 
ator will give an alternating current. 

The current induced in the armature of any dynamo 
will be alternating, but it may be taken off in the external 
circuit in one direction, and a generator built to do this is 
called a direct current generator. It differs from the alter- 
nating type in having a commutator ring to which the ends 



286 The Boys^ Own Book of Great Infventions 

of the armature loop are joined instead of collector rings. 
This commutator ring is split and the two segments are 
insulated from each other and from the shaft. The brushes 
are so placed that, just at the instant that the current 
reverses in the loop, the segments of tlie commutator 
change contact with the brushes. The segment that has 
been in contact with the positive brush moves over and 
touches the negative brush and the other segment comes 
in contact with the positive brush. Thus, although the 
direction of the current changes in the armature, it does 
not change in the external circuit. The diagram of a 
simple direct current generator is shown at B in Fig. ii. 

In the dynamos built by Wilde and other experimenters 
of that time electro-magnets were substituted for the per- 
manent steel magnets used by Faraday. But these mag- 
nets had to be separately excited by small generators with 
permanent magnets. The first improvement upon this 
method was made by Siemens, a German, who found that 
a shunt circuit taken from the armature and passed about 
the field magnets would furnish the necessary current for 
this purpose and still leave an abundant supply for the 
external circuit. He also improyed the armature by wind- 
ing the wire lengthwise of a soft iron drum. A little later 
several coils of wire v*^ere wound upon the drum of the 
armature, placed at angles to each other and connected in 
series through the segments of the comjnutator ring, there 
being as many segments as there were loops. This pro- 
duced a more uniform voltage because at any moment the 
various loops would be cutting the lines of force at all 
angles and therefore inducing voltages from a minimum 
to a maximum. 

One of the early troubles with the Siemens dynamo was 
excessive heating of the core, but this was remedied by 




Early Edison dynamo, Colton motor and General Electric direct-current arma- 
ture and generator. 



Two Centuries of Electricity 287 

Gramme of France who reinvented the ring armature of 
the Italian, Pacinotti, and produced in 1868 the first really 
successful dynamo for strong currents. This ring was a 
hollow soft iron cylinder upon which the wire was wound, 
and it will be seen that but one-half of each loop cut the 
lines of force. For this reason the drum type is more 
widely used now, but it is made up of a large nmnber of 
soft iron sheets cut to shape and insulated from each other. 
This reduces the heating efifects in the core by preventing 
very largely the induced "eddy" currents which cause them. 

Edison made very great improvements and introduced 
the compound dynamo. In the shunt wound dynamo a 
decided drop in voltage occurred when a large demand was 
made upon it. As the current in the external circuit in- 
creased, less flowed through the shunt circuit about the 
field magnets and there being fewer lines of force less volt- 
age was generated. To remedy this Edison passed the 
wires leading to the external circuit in a number of turns 
about the field magnets, too, and therefore whatever the 
change in the current in the external circuit the strength 
of the field remained constant. A change in one circuit 
was balanced by a change in the other. Edison also intro- 
duced the practice of placing the dynamo on the same shaft 
with the engine which drives it. For electric lighting and 
where constant voltages must be maintained these im- 
provements were of immense importance. 

One other fact about the dynamo must be mentioned. 
At the same time the engine turns the armature and in- 
duces a current, the armature is constantly endeavoring to 
run backward as a motor. This is called the ' ' motor-effect ' ' 
of a dynamo, and upon the extent of it depends the amount 
of work that the engine must do. The magnitude of this 
effect will depend upon the quantity of current that is 



288 The Boys^ Own Book of Great Inventions 

being drawn from the dynamo. The greater this is the 
harder the engine must work. When no current is being 
taken and the dynamo is generating nothing but voltage, 
practically no work is required of the engine, but as the 
amperes and watts increase the demand upon the engine 
is correspondingly increased. 

For high voltages and long distance transmission huge 
alternators are used, but where low voltages are required 
for nearby use direct current generators are preferable and 
for much work direct current is indispensable. 

The Electric Motor. — It was early found that if current 
were passed into the armature of a dynamo it would run 
backwards as a motor. A motor is essentially a reversed 
dynamo. The motors that drive the submarines, when 
submerged, are run as dynamos by the Diesel engines when 
lying on the surface and are used to charge the storage 
cells. As a motor the magnetic field of the field magnets 
reacts on the field of the armature and the latter is made 
to rotate. Not until the modern dynamo had been per- 
fected, however, was a practical motor possible. 

One of the first applications of the electric motor was 
for street railway traction. The first of these roads was a 
i,ooo foot ''electrical merry-go-round" set up in BerKn at 
the Industrial Exposition held there in 1879. But it is to 
Edison that the world is indebted for the real perfection of 
the electric motor. He showed the necessity for a starting 
resistance and developed the modern street car controller. 
In his early experimenting with electric locomotives he 
found that the sudden rush of current through the arma- 
ture would burn out the winding before the armature 
could get started. Therefore he introduced resistance in 
series with the armature, which was gradually cut out as 
the motor gained speed. To understand the necessity 



Two Centuries of Electricity 



289 



for this we must note that at the same time the armature 
of a motor is turning, it is also cutting lines of force just as 
a dynamo does, and, therefore, is inducing a counter elec- 
tromotive force. This is called the ''dynamo-effect" of a 
motor. This counter E. M. F. acts as resistance and pre- 
vents injury to the armature, but until it has had dme to 
develop, a starting resistance must take its place. What 
runs the motor is the difference between the impressed 
voltage and its counter E. M. F. 

One very good illustration of the interchangeabihty of 
the dynamo and motor is to be found in some types of self- 
starters on automobiles. The starter consists of a small 
electric motor run by a set of 
storage batteries. But after 
being started the engine runs 
the motor as a dynamo and 
generates current to charge the 
storage cells. When the cells 
are charged the generator is 
automatically cut out. 

TWO EXPERIMENTS WITE THE 
MOTOR 

I. The Motor Effect.— To 

learn the reaction effects of two 

magnetic fields upon each other 

arrange apparatus as shown in 

Fig. 92. Into a small base 

board fit a wooden upright and 

clamp to it a holder carrying a strong horseshoe magnet. 

Fit binding posts in the base and connect to them a bent 

piece of No. 28 spring brass wire so that the horizontal 

portion will come midway between the two poles of the 





Fig. 92. 



290 The Boys^ Own Book of Great Inventions 

magnet. Now connect with the binding posts two dry 
cells and as the circuit is made note the effect on the brass 
wire. Make and break the circuit and observe the vibra- 
tion of the wire. 

The lines of force from the magnet react with the lines 
of force encircling the wire to produce attraction on one 
side of the wire and repulsion on the other. The result is 
motion. In a motor the same effect occurs. Twice during 
each revolution of the armature the current in it is reversed 
by means of the commutator in order to produce contin- 
uous motion. 

2. A Simple Motor. — ^A simple motor may be made in 
accordance with the diagram in Fig. 93. Arrange a wooden 
base board, upright and cross arm as shown. Through 
holes in the cross arm suspend a strong horseshoe magnet 
of fairly good size. On the base board place a piece of 
glass and on it mount a shaft to carry the commutator and 
armature. The armature will consist of a wooden disk D, 2 
inches in diameter and half an inch thick carrying two bolts 
about 2 inches long. On the upper two-thirds of each bolt 
wind 10 feet of magnet wire in such a manner that the 
upper end of one bolt will be a north pole and the upper 
end of the other a south pole. The rule for determining 
the polarity of an electro-magnet is this: Grasp the magnet 
in the right hand with the fingers extending about it in the 
direction the current flows and the thumb will point to the 
north pole. Secure the armature to the shaft and lead the 
wires to the commutator below. 

About a quarter of an inch below the armature the 
commutator will be placed. This will consist of a wooden 
disk about an inch in diameter upon which two strips of 
copper or brass are tacked. There should be space be- 
tween the ends of these strips on each side and it would be 



Two Centuries of Electricity 



291 



well to cover the disk with rubber before tacking the strips 
on. Two wooden posts on each side of the commutator 
should carry brass strips 
which press against the seg- 
ments of the commutator 
ring. These are the brushes. 

Now connect the wires 
leading from the brushes with 
one or two dry cells and a 
very brisk rotation will be 
set up. The north pole of 
the field magnet repels the 
north pole of the armature 
and attracts its south pole. 
The south pole of the field 
magnet acts in a similar 
manner upon the poles of 
the armature and rapid mo- 
tion is the result. 

In dynamos and motors 
we have some of the best ex- 




By courtesy of Boys' World. 

Fig. 93. — ^An easily constructed 
motor. 



amples of the transformation of energy. The mechanical 
energy of falling water may be made to turn a water wheel, 
the shaft of which is coupled to a dynamo. The armature 
of the dynamo in being made to cut magnetic fines of force 
generates electrical pressure and the currents taken from 
it will run motors, produce fight and heat and effect chem- 
ical changes. For the falfing water may be substituted the 
heat energy of burning coal. And if we consider that both 
the energy of the falling water and that of the coal are 
dependent upon the sun we see that in the last analysis 
the sun is the source of aU the energy used upon this 
planet. 



292 The Boys^ Own Book of Great Inventions 

TWO LARGE POWER PLANTS 

The Ford Plant. — In 19 17 the Ford Motor Company at 
Detriot, Mich., completed the world's largest direct-current 
power plant. The huge dynamos there installed are the 
largest units of the direct-current type ever built and have 
a total maximum output of 65,000 kilowatts, or approxi- 
m^ately 87,000 horse power. This immense amount of 
power is used to run the motors connected with more than 
8,000 machines distributed over a floor space of 47 J^ acres. 
These generators, too, supply current for the motors of the 
ventilating system and for the lighting circuits of the plant. 

The giant field frames of one of these dynamos is 21 feet 
high and 26 feet across the supporting legs. Each complete 
generator weighs 105 tons. Five tons of copper, an amount 
sufficient to make 60 miles of No. 10 wire, are used in its 
construction. Owing to their immense size it was neces- 
sary to construct and ship these d3aiamos in parts, and four 
freight cars were required to transport the parts of a single 
machine. 

The power developed by each d3rnamo is 3,750 kilowatts 
at a pressure of 250 volts and 80 revolutions per minute. 
This quantity of electric energy is sufficient to Hght 150,000 
25-watt lamps or 7,500 arc lamps. It is equivalent to 5,000 
horse power and a single dynamo would run 300 street cars. 
Fifteen thousand amperes of current are supplied contin- 
uously by each dynamo and 260,000 amperes by the whole 
plant. The total output is one-eightieth of the potential 
capacity of Niagara and would be sufficient to meet the 
entire electrical needs of many cities of 50,000 population. 

To drive these generators fourteen 6,000 horse power and 
one 4,000 horse power reciprocating engines of the gas-steam 
type and one 1,500 horse power straight steam engine are 




View of generators and engines in the Ford power plant. 



Two Centuries of Electricity 293 

direct-connected to their shafts. The water used in cool- 
ing their hot parts leaves the engine at a temperature of 
175° Fahr. and is used for boiler feed and hot- water factory 
supply. The hot exhaust gases maintain the temperature 
of the steam between the high and low pressure cylinders 
of the steam engines, after which they pre-heat the boiler 
feed water. 

The steam units are of the double expansion CorKss type. 
In the boilers which supply them are i ,800 tubes having a 
heating surface of approximately 26,000 square feet, and 
when all fourteen boilers are in operation they consume 
2,000 tons of coal and evaporate 22,000 tons of water dur- 
ing each 24 hours. Three thousand gallons of lubricating 
oil are handled per hour by the filters which supply the 
engines and dynamos. 

The switch board which controls this electrical system 
is 424 feet long and contains 222 dark Tennessee marble 
panels. Its cost was $400,000, or nearly $1,000 per running 
foot. Approximately 165 tons of copper were used in its 
construction and at present prices would be worth about 
$100,000 in the raw state. 

The whole power plant is controlled by an elaborate 
signal system which insures continuous service at all times. 
A 200-pair telephone switch board connects with engine- 
operating stands, boiler rooms and every distribution 
center in the plant. In the office is a signal panel carrying 
300 signal lamps and a duplicate set of telephone terminals. 
A green lam-p lights on this panel when a feeder is in service 
and is replaced by a red lamp when out of operation. Thus 
any trouble in the system is easily located. 

This plant is a marvel of engineering design and con- 
struction and a monument to American enterprise. 

The Niagara Plant. — For nearly twenty-five years a 



294 The Boys^ Own Book of Great Inventions 

small portion of the energy of Niagara Falls has been 
utilized for the production of electrical power and there 
has grown up about the great waterfall one of the largest . 
and busiest industrial centers of the world. Here those 
electro-chemical processes which were discovered and first 
employed by Sir Humphrey Davy find their greatest de- 
velopment in a large number of varied and complex chem- 
ical industries. Could this brilliant chemist of more than 
a century ago visit these wonderful plants and observe, on 
the enormous scale there displayed, the practical operation 
of the processes created by his own genius, how completely 
he would see his dreams fulfilled. 

These power plants that dot the brink of the Niagara 
River generate alternating current and have a total capac- 
ity greater than that of any other similar combination of 
plants in the world. In all, six or seven hundred thousand 
horse power of electric energy are here developed. But 
before this energy of Niagara's waters could be utilized the 
high voltage alternating current dynamo and the trans- 
former had to be perfected. Within Httle more than ten 
years from the coming of the first successful commercial 
dynamos ground was broken for the first Niagara power 
plant. Marvelous progress had been made in this short 
period. Electric machinery had been brought to a point 
such that the ^'harnessing of Niagara" might cease to be 
a dream and become a fact. 

About a mile above the Falls a canal leads a few hundred 
yards back from the river and on its banks on either side 
stand the power houses of one of the main stations of the 
Niagara Falls Power Company. Beneath each power 
house is a series of penstocks connected with the water in 
the canal and having a sheer drop of i8o feet. At the 
bottom of each penstock is placed a turbine water wheel 



Two Centuries of Electricity 295 

which utilizes the kinetic energy in the falling water and 
passes the spent water into a tunnel running beneath the 
city of Niagara Falls and emptying into the river just 
below the suspension bridge. There are 1 1 of these in one 
power house and 10 in the other. From each turbine there 
extends a shaft into the power house above, which carries 
at the top a generator having a capacity of 5,500 horse 
power. In the power houses on the Canadian side these 
generators develop as high as 12,500 horse power. They 
make 250 revolutions per minute and generate electrical 
pressures of 2,200 volts on the American side and 12,000 
volts on the Canadian side. Like huge tops, day and 
night, unceasingly, without vibration and with little sound 
these dynamos spin. 

A part of the immense amount of power generated is put 
through step-down transformers and converters for use 
in the multitude of factories clustered about the Falls. 
The rest is stepped up to high tension currents of 60,000 
volts in some cases and transmitted to distant cities. The 
street cars of Buffalo are run with power from Niagara 
Falls and its streets are lighted with energy from the same 
source. For long distance transmission high voltages and 
small amperages make possible the use of much smaller 
wires, saving enormously in copper, and also reduce many 
times the heat losses in forcing currents through the line. 
Where this power is to be used it is stepped down to small 
voltage and large quantity suitable for motors and Hght- 
ing purposes. 

Waste Water Power. — ^The conversion of the waste water 
power of the coimtry into electrical energy for nmning our 
mills and street cars and lighting and heating our homes is 
one of the most urgent problems of the present century. 
There are going to waste on government lands in the 



296 The Boys^ Own Book oj Great Inventions 

United States a continuous flow of 28,000,000 horse power. 
To produce this same amount of power by burning coal 
would require 390,000,000 tons per year, or two-thirds of 
the total output. In addition to the waste water power on 
government lands there are large quantities under private 
ownership also unutilized. With the constantly increasing 
demands for fuel and its growing scarcity self-interest and 
necessity will compel action in the near future. A water 
fall is not essential to the development of power. Any 
stream with any considerable volume of w.ater and a strong 
current possesses energy readily available. Before this 
century passes a tremendous expansion in the development 
and utilization of electric power is bound to come. The 
age of the dreamer and the inventor is yet here, and still 
greater triumphs He just beyond the veil that separates the 
present from the future. 

A Great Achievement in Railway Electrification. — One of 
the most remarkable triumphs of Rocky Mountain rail- 
roading is the electrification of 440 miles of the Chicago, 
Milwaukee and St. Paul Jines. This division including 
some of the most rugged and formidable mountain scenery 
of the West was electrified and put into operation in 19 15. 
Forty-two giant locomotives, the mightiest of any type in 
the world, are employed upon it. Each locomotive weighs 
284 tons and is driven by eight massive 420-horse power 
motors, making a total motive force of 3,440 horse power. 
These motors are run by direct current at a pressure of 
3,000 volts fed into them through controUing devices of 
great complexity. 

The power for these locomotives is suppKed by the 
Montana Power Company, located on the Missouri River 
at Great Falls, Montana. At this point for a space of eight 
miles the river drops 400 feet, one-half of the drop being 




Electric locomotive and passenger train on the Chicago, Milwaukee and St. Paul 
Railway, and power house of the Niagara Falls Power Company. 



Two Centuries of Electricity 297 

an abrupt descent. A total of 139,000 horse power is de- 
veloped here, a part of which is sold to the Chicago, Mil- 
waukee and St. Paul Railway. Still larger outputs are in 
process of development and more miles of the road will be 
electrified in the near future. This power is passed to the 
sub-stations along the line as alternating current at pres- 
sures of 100,000 volts. In these stations it is stepped 
down to 2,300 volts and converted into direct current at 
3,000 volts pressure for use in the motors. 

Probably the most unique feature of these locomotives 
is their system of "regenerative braking." Ordinarily this 
must be accomplished by air pressure and brake-shoe 
friction, but in this system no brakes are employed. Refer- 
ence has already been made to the fact that a reversed 
dynamo is a motor and a reversed motor is a dynamo. 
Therefore, when an electric-drawTi train comes to a down- 
grade the power is shut off, and the motors being turned as 
dynamos by the energy of the descending train develop 
electric power which is returned to the Kne, and in so doing 
the speed is restricted within the limits of safety. The 
train is made to do work, and the faster it goes the more 
work it must do. The capacity of these reversed motors 
is so great that excessive speeds are impossible. The 
power returned to the line is used to run other locomotives 
along the division, and any in excess of this is passed through 
meters of the Montana Power Company and is automat- 
ically placed to the railroad company's credit. 

These locomotives are used for both passenger and 
freight service. Very much heavier trains can be hauled 
and greater speeds obtained than are possible with steam 
locomotion. Wherever possible electric traction is destined 
to be the locomotive power of the future. 

Since those first simple electrical experiments of more 



298 The Boys^ Own Book of Great Inventions 

than two centuries ago to the mighty achievements of 
to-day a long road has been traveled. Very slowly at first 
but in recent years with tremendous swiftness, this myste- 
rious manifestation of energy has been mastered and made 
tributary to the needs of the world. The Hghtning of 
Franklin and the electricity of Volta and Faraday have 
been requisitioned for the service of mankind. The first 
real sovereignty of Nature began with the mastery of 
electricity. 



Chapter XV 

THE EVOLUTION OF ARTIFICIAL 
ILLUMINATION 

From the foul smelling, smoke-producing oil lamps of 
the ancients to the tallow candle of a century ago and the 
great '^ White Ways" of to-day, stretches a long pathway 
of scientific discovery and invention. Night has literally 
been turned into day and the dazzHng brilUancy of gas and 
electric methods of illumination are to be counted among 
the crowning glories of modern inventive genius. What 
the flower is to the plant so is artificial illumination to the 
scientific discoveries back of it. 

Practically all of the epoch-making progress in artificial 
hghting has come about in the last forty years. In the 
days of Caesar and for long centuries after, the king's palace 
and the peasant's hut, alike, were Hghted with a crude sort 
of lamp — Kttle more than a vessel filled with oil into which 
was dipped a wick. So sluggish was the progress in all 
things practical that for centuries nothing better was 
demanded. And then toward the close of the twelfth 
century came the tallow candle, which was as much of an 
improvement over the ancient oil lamp as the electric Hght 
is over the candle. The candle was smokeless and odorless. 
It burned with ^' great brilHancy" and for the first time in 
history the world was ''well Hghted." 

The improved oil lamp in Europe dates from the time of 
the French Revolution. Only animal and vegetable oils 
were burned in it, for mineral oils were but Httle known, 

299 



300 The Boys^ Own Book of Great Inventions 

In this country, not until after the discovery of petroleum 
in 1859 were lamps used to any extent. In the pioneer's 
cabin the pine torch or more often the open fireplace 
afforded the only Hght. In the more thickly settled por- 
tions the tallow candle held sway until long after the mid- 
dle of the century. But with the discovery of petroleum 
and the perfection of methods for refining it came the new 
era of the kerosene lamp — still widely used in village and 
farmhouse. 

Davy early in the century had demonstrated the possi- 
bility of the electric arc lamp, rivaling in brilKancy the 
light of the sun. But in those days batteries were the only 
source of current and such an expensive method was im- 
possible. Nevertheless, numerous experimenters continued 
to devise more or less successful electric Kghts for half a 
century. Not, however, until Faraday in 183 1 discovered 
the principle of the dynamo, did electric Kghting become 
commercially practicable. Even then, nearly forty years 
passed before the invention of a successful dynamo. But 
in the meantime the very great improvement in battery 
construction had made possible electric Kghting for exhi- 
bition purposes. The first electric Kght was used in France 
in 1849 during the production of an opera in which it was 
desired to have the sun appear. When in 1868 the Gramme 
Ring dynamo was invented commercial currents were 
available and success assured. 

The first electric. Hght to be widely adopted was the 
^'Jablochkoff candle" invented by a Russian in 1876. It 
consisted of two carbons placed side by side in a vertical 
position and insulated from each other below. The tips of 
the carbons were joined by a thin strip of carbon to start 
the arc, but this almost immediately burned away. As the 
dynamos then in use produced only alternating current the 



The Evolution oj Artificial Illumination 301 

two carbons burned off together. This arc lamp gave a 
very satisfactory light and gained at once a tremendous 
popularity. It was quickly introduced into almost every 
region of the world including countries in South America 
and Asia. For street lighting the arc lamp was unexcelled. 
The automatic feed and cut out, the glass inclosed arc and 
improved methods of manufacturing carbons quickly 
followed. 

Edison and the Incandescent Lamp. — Still the small 
electric lamp for home and office had not come. But 
the man possessed of the indefatigable industry, the pa- 
tience and the genius necessary for its perfection was at 
work in his laboratory. Thomas A. Edison at Menlo 
Park, New Jersey, set himself to produce a lamp that 
combining efficiency and cheapness with simpHcity and 
utility should be suitable for universal use. This was in 
1878. Very early in his experimenting he gave up the idea 
of an arc lamp and became convinced that a filament which 
should be heated to incandescence by its own resistance to 
the electric current offered the proper solution. But how 
to get such a filament was the problem. All lamps of this 
type had been unsuccessful. The filaments burned out 
almost immediately and other scientists declared the thing 
*' impossible." But it is the mark of genius to accompHsh 
the impossible and Edison, though not recognized as such 
then, was a genius. 

Edison's first experiments were with fine platinum fil- 
aments, but platinum was expensive and proved unsatis- 
factory. He then turned to carbon as the ideal substance 
for his purpose. On October 21, 1879, after many trials he 
mounted a carbonized sewing thread in a glass globe from 
which he exhausted the air. Upon passing a current 
through this filament it Hghted to brilliant incandescence 



302 The Boys^ Own Book of Great Inventions 

and continued to glow brightly for more than forty hours. 
The carbon filament lamp was a success, and one more step 
had been taken toward ''the banishment of night." 

Eut the carbon filament was only in its infancy and far 
from perfection. Edison set his assistants to carbonizing 
every organic substance imaginable in the hope of finding 
an ideal filament. Carbonized paper proved better than 
thread. It was cut into the shape of a horseshoe and 
heated under pressure, out of contact with the air. In less 
than a month several hundred of these paper filament 
lamps had been made and put into actual use in the labo- 
ratory and in the streets and residences at Menlo Park. 
Excitement ran high. On New Year's Eve, 1879, special 
trains were run from New York and nearby cities to wit- 
ness a pubHc exhibition of the new lamps. More than 
three thousand persons availed themselves of the oppor- 
tunity. 

Still Edison was not satisfied with the paper filament 
lamp and the search for a better substance was continued. 
One day he observed a palm-leaf fan lying on his laboratory 
table. He was impressed with the long fibrous filaments 
in its rim and handed it to an assistant with instructions 
to carbonize them. The result was more satisfactory than 
anything else that had been tried and Edison sent a man 
to Japan to find the best variety of bamboo fiber. But he 
did not stop there. Men were sent to ransack the earth 
for a better natural product, and at last from the wilderness 
of the Amazon the ideal material was brought back. It is 
said that the search for this fiber cost nearly $100,000. 
But when the man of genius sets to work no obstacle can 
impede his progress. 

Later the plan was adopted of dissolving cotton wool in 
zinc chloride solution and squirting it through a small hole 




Laboratory at Menlo Park where Edison made his first electric lamp. 




A few of the types from the paper filament lamp to the nitrogen- 
filled bulb. 



The Evolution of Artificial Illumination 303 

into a tank of alcohol. This formed an elastic filament 
which hardened in the alcohol and when carbonized proved 
superior to the bamboo fiber. Such lamps consumed about 
3.5 watts per candle power and had an average Hfe of 1,000 
hours. The lamp itself underwent a gradual evolution in 
form of globe and shape of filament. Some of these forms 
are shown in accompanying cuts. 

A metallized filament lamp, called the gem, which re- 
duced the watts per candle power to 2.5 appeared in 1905. 
In the following year the tantalum lamp, the filament of 
which was made from the rare earth metal of that name, 
came on the market but was quickly superseded by the 
more efficient tungsten lamp. This was in 1907. Six 
years later in the Research Laboratories of the General 
Electric Company, it was found that an inert gas Hke 
nitrogen placed in the globe of a tungsten lamp would 
increase several times the candle power per watt and give 
a Hght of great brilKancy. The world is now familiar with 
the nitrogen-filled bulb, giving an efiiciency of more than 
one candle power per watt. 

Such in brief is the story of the incandescent lamp which 
has done more to dispel the darkness of the earth and usher 
in the "sunshine" than any other invention in all history. 

Gas Lighting. — The improved electric light, however, 
was not to enjoy a monopoly of the field of artificial illumi- 
nation. For nearly a century the open gas flame had been 
a strong competitor of the candle and the oil lamp. Then 
early in the eighties, as a result of research work by Dr. 
Carl von Welsbach on the rare earth metals, the incandes- 
cent gas mantle was invented and the rejuvenated gas 
light at once became a strenuous rival of the infant electric 
lamp. 

Dr. von Welsbach was exanaining the rare earth metals 



304 The Boys^ Own Book of Great Inventions 

with the spectroscope. To do this it was necessary to raise 
them to a state of incandescence. One day the idea oc- 
curred to him that he might increase this incandescence by 
saturating a piece of cotton cloth with a solution of the 
metals and burning it in a Bunsen flame. The idea was 
immediately put into execution and not only was the 
incandescence increased but the cotton fiber burned away, 
leaving a skeleton of metallic oxides which continued to 
glow with great brilliancy. At once Welsbach conceived 
another idea, that of a gas mantle to be made by saturating 
a cotton fabric with solutions of these metals and, when 
the organic matter had been burned away, to allow a gas 
flame to play over its surface. In the work that followed 
he found that the oxide of thorium gave the most satisfac- 
tory results. He also discovered that the more pure the 
oxide was the less Hght it gave. Evidently the brilHant 
Hght-giving properties were due in part at least to the 
presence of some other substance. Investigation revealed 
traces of the oxide of cerium, another rare earth metal. 
But as the result of a prodigious amount of research it was 
found that only one per cent of this oxide was required. 
At last the gas mantle formula was given to the world, and 
it proved the salvation of an industry that with the tallow 
candle and the oil lamp seemed destined to become obso- 
lete. 

These gas mantles are made by fashioning "stockings" 
from a special quahty of cotton fabric and saturating them 
in a solution of the nitrates of these rare earth metals. 
These are slipped over a glass form to dry. A loop at the 
top with which to suspend the mantle over the burner is 
made from asbestos fiber. When dry a flame is appHed 
which burns away the cotton and changes the nitrates into 
oxides. This leaves the skeleton in a very delicate con- 



The Evolution of Artificial Illumination 305 

dition, too fragile for shipment. To strengthen it the 
mantle is dipped into a mixture of copal, shellac, alcohol, 
ether and camphor or often into a mixture of collodion and 
castor oil. When hung over a burner and first Ughted it is 
this mixture that burns away. 

This is simply one of the numerous instances in which 
the research chemist has made discoveries, very often 
accidental, which have proved to be of tremendous com- 
mercial importance. It is the trained chemist who is able 
to do original research that can solve the big problems of 
industry and will command the large salaries paid to men 
of science. 

The Acetylene Light. — In the last decade of the nine- 
teenth century in the very high temperature of the electric 
furnace, a compound was formed which united directly 
with water to give a gas of high candle power and a beau- 
tiful white Hght more closely approaching sunlight than 
any other light known. The substance was calcium car- 
bide and the gas acteylene, both now very familiar to the 
pubhc. The carbide is made by heating together lime and 
coke. At the high temperature of the electric furnace the 
coke, which is almost pure carbon, not only unites with the 
oxygen of the lime to form the gas carbon monoxide but 
also combines chemically with the calcium, leaving a dark 
brown substance called calciimi carbide. So unstable is 
this carbide that water readily attacks it with the produc- 
tion of acetylene gas, and slaked lime. 

The gas has a very disagreeable fish-like odor and is 
highly explosive when mixed with air. Many accidents 
occurred in the early days of acetylene lighting, but genera- 
tors have been devised which eliminate all danger and the 
plants now manufactured for country districts have proved 
a boon to farms and villages not served by gas and electric 



3o6 The Boys^ Own Book of Great Inventions 

companies. The cost of operation is exceedingly low, and 
this, combined with the soft white Hght emitted by the 
burning gas, has made the acetylene Hghting system a very 
strong competitor of the private electric plant for country 
and suburban use. 



EXPERIMENTS WITH ELECTRIC LIGHTING 

1. To show the necessity for exhausting the air from the 
globe of an incandescent lamp, select an old lamp and with 
a pair of pliers carefully break off the tip. Now make a 
tiny hole at this point and let in the air. Then screw the 
lamp into a socket and turn on the current. It will flash 
up brilliantly and then go out, the filament having been 
burned away at one or several points. This is due to the 
oxygen in the globe. 

2. Between the binding post of the asbestos covered board 
made in Experiment 3 under the Heating and Chemical 

Effects of the current, place a 
piece of No. 30 iron wire. Con- 
nect this with a dozen dry cells 

or in series with the rheostat 

\ \v.'i' r - ^ W J / and house current. The wire 
ELECTRIC LAMP "^^^ ^^ heated to mcandescence 

„ — for a few moments and then bum 

Fig. 94. 

away. 

3. But if the wire in the previous experiment could be 
placed in a vacuum or in air from which the oxygen had 
been removed it would continue to glow for a long^ while. 
To remove the oxygen, invert a drinking glass over water 
in a shallow dish as shown in Fig. 94. Cover the copper 
lead wires passing underneath its edges with small rubber 
tubing to insulate them from the water and bend them up- 




The Evolution of Artificial Illumination 307 



ward, leaving a small gap at the top for the filament. On 
the surface of the water, float a small crucible containing a 
little alcohol. Insert a filament of fine iron wire and light 
the alcohol with a match. Immediately cover the crucible 
and filament with the inverted tiunbler and wait for the 
flame to disappear. The burning alcohol will remove the 



RIM or BortTUE 




PINCH COCKr> 



TOP VIEW OF 
wire: SUPPORT 




ACETYLENE EWRNER 

RUBBER CONNECTION 
CLASS TWBINO 

rubbcb stopper 
— wire: support 



WATER 
CALCIUM CARBIDE 



:-r--3^ -f^^: ~ PERFORATED LEAP DISC 



Fig. 95. — ^Acetylene lamp. 

oxygen from the air under the tumbler. Now connect the 
copper lead wires with cells or the house current and rheo- 
stat. The filament will light up and continue to glow 
indefinitely provided the oxygen has all been removed. 

German silver wire may be substituted for iron, and 
perhaps you can insert a very fine splinter of willow char- 
coal. 

Homemade Acetylene Lamp. — A very simple form of 



3o8 The Boys^ Own Book of Great Inventions 

acetylene lamp can be easily made by anyone from the 
following materials: 

A large-mouthed bottle of one to two quarts capacity, 
a lamp chimney, small lead disk, one-holed rubber stopper, 
6 inch piece of glass tubing, rubber connection, acetylene 
gas tip and i8 inches of aluminum or other heavy wire. 

Put the apparatus together as shown in the diagram. 
The lead disk may be perforated with a hammer and nail 
punch. Then fill the lamp chimney two-thirds full of 
lumps of calcium carbide and pour water in the bottle. 
Open the pinch cock and the water will rise through the 
lead disk and coming in contact with the carbide will gen- 
erate the acetylene which in a few moments may be Hghted 
at the burner. 

The wire support may be made by placing two sets of 
aluminum wire about the chinmey at right angles to each 
other and twisting the ends together with pHers. 

When once charged the lamp will give a good light for 
a considerable period and will be found useful in workshops 
and wherever gas or electricity are unavailable. To re- 
charge, remove the stopper, clean out the chimney and 
refill with carbide. The higher the water in the bottle the 
greater the gas pressure. 



Chapter XVI 
FIRE AND HIGH TEMPERATURES 

The superiority of primitive man to the wild beasts about 
him and the first great step toward the conquest of nature 
must have been demonstrated in his mastery of fire. Not 
until that time arrived could he have been very far re- 
moved from the man-like animals from which he had 
descended. Very early the phenomenon of fire must have 
attracted his notice. The volcanic eruption, the lightning 
flash or, perhaps, the rubbing together of two dry branches 
in a strong wind very frequently kindled fires. Appealing 
at first, doubtless, only to his superstition, the grateful 
warmth of these fires added to his sense of comfort and 
aroused a desire to perpetuate them. By their aid he 
cooked his food, fashioned his implements and Kghted his 
cave. But for how many centuries this use of fire extended 
only to a knowledge of the means of feeding and perpet- 
uating it, we do not know. When, however, either by the 
rubbing together of two dry sticks or by the chance spark 
from a flint and steel, he learned to kindle a fire himself, 
his first real mastery of it began. The camp fire before his 
open cave lured wild animals within his range. With its 
aid he dried and toughened the wood which he shaped into 
formidable instnmients of warfare. Very gradually through 
his experiences with fire he acquired a rudimentary knowl- 
edge of the arts of pottery, glass making and the metal- 
lurgy of the simple ores. 

And so it has been from the time of the cave dweller to 

309 



310 The Boys^ Own Book of Great Inventions 

the present day. Just as man's knowledge of fire — ^its 
origin, its explanation and applications have expanded, so 
has his proficiency in the arts and industries grown. There 
is scarcely an article that ministers to our physical comfort 
which has not somewhere come under the influence of fire. 
From the village forge to the steel mill and throughout the 
wide range of manufactures, fire is a fundamental requisite 
of success. When fuel cannot be had, factories close, loco- 
motives cease to run, our streets and houses are in dark- 
ness, and industry in general is at a standstill. Not only 
is fire essential to all industrial progress, but high tempera- 
tures are equally important. With each advance in the 
degree of heat obtainable in our furnaces, have come 
additional triumphs of science and new commercial proc- 
esses. The alchemist in his vain endeavor to transmute 
the baser metals into gold, knew no higher temperature 
than that possible with good beech wood. Then came coal 
and gas with the forced draft, to be followed by the oxy- 
hydrogen blowpipe, the electric furnace, thermit, the oxy- 
acetylene torch and the explosion of cordite. Temperatures 
now rivahng those of the sun are within our grasp and 
subject to our control. 

The oxy-hydrogen blowpipe for many years represented 
the acme of high temperature attainment. Not very long 
ago its use for the production of the ^'limelight" in the 
stereopticon was very common. Large pressure tanks 
containing oxygen and either hydrogen or coal gas were 
connected to an especially constructed blowpipe having a 
tube through the center for the passage of the oxygen and 
surrounded with a jacket for the hydrogen. The gases 
mixed in proper proportions at the nozzle and burned with 
a temperature of about 2000° Centegrade. When this 
flame was played over a stick of quicklime, the lime was 



Fire and High Temperatures 311 

heated to a brilliant incandescence and was formerly the 
only method of producing a strong light for stage and 
lantern projection. This flame, too, was used for glass 
working, for making artificial gems, for melting platinum 
and wherever the ''highest" temperatures were required. 
And then toward the close of the last century came the 
electric Hght with its greater efficiency, higher power and 
extreme simpKcity and convenience. The limeKght went 
the way of the candle and the oil lamp, and the oxy-hydro- 
gen flame was retained only for minor operations. 

Professor Henri Moissan of Paris did the first important 
work with the electric furnace and in a series of researches 
now classic this brilKant French chemist produced a large 
number of carbides of both the metals and the non-metals. 
A carbide is a compound of carbon and another element, 
of which carborundum and calcium carbide are the two 
most common examples. His crowning achievement, 
however, was the production of artificial diamonds. A 
diamond is simply crystaUized carbon. Moissan knew 
that small diamonds are sometimes found in meteoric iron 
which bears evidences of having been subjected to great 
heat and probably high pressures. It therefore occurred 
to him that possibly carbon dissolved in molten iron and 
then plunged into cold water would also crystalHze into a 
genuine diamond. Accordingly he placed a mixture of 
charcoal and iron in a carbon crucible and covered it up in 
his electric furnace. After about six minutes he removed 
the crucible containing the molten iron and dissolved 
carbon with a pair of tongs and plunged it into a tank of 
water. A great boiling and seething followed but no ex- 
plosion. The iron soHdified, subjecting the carbon to tre- 
mendous pressure, and when the mass was treated with 
strong acids and other chemicals the residue showed the 



312 The Boys^ Own Book of Great Inventions 

presence of microscopic diamonds. The thing had been 
done, and it only remains for some other chemist to make 
diamonds of commercial size. 

The furnace employed by Moissan was of the arc type 
and consisted of two fire bricks placed one on top of the 
other. On either side was a groove for the carbon electrode 
and in the center a cavity for the crucible. The cover 
brick was hollowed out slightly to increase the size of the 
cavity and to reflect the heat of the arc back into the 
crucible. The arc was identical with that produced by 
Davy nearly a century before and gave a temperature 
close to 4000° Centegrade. 

One of the first appKcations of the electric furnace in a 
commercial process was by Dr. Edward G. Acheson in the 
production of carborundum. Carborundimi is the stuff 
with which the dentist drills the cavities in your teeth and 
one of the greatest artificial abrasives known. Back in 
189 1 Dr. Acheson was looking for a material which would 
be superior to emery for grinding purposes. For his fur- 
nace he used an ordinary plimiber's bowl which he filled 
with a mixture of coke and clay. One of the wires from his 
dynamo he connected to the bowl and the other was thrust 
into the mixture. When he turned on the current the 
mass gradually fused, and as he withdrew the wire after a 
time there were found clinging to it a few very small, 
sparkling crystals. Cautiously he removed the crystals 
and picking them up on the point of a pencil drew the 
pencil across a pane of glass. They readily scratched the 
glass and Dr. Acheson knew that in these hard, sharp, 
brilliant diamond-like crystals he had found a new abrasive. 

The experiments were continued and, when enough 
crystals to fill an ounce bottle had been made, Dr. Acheson 
put them in his pocket and hurried to New York. There 



Fire and High Temperatures 313 

he sold them at 40 cents per karat to a prominent firm of 
jewel polishers as a substitute for diamond dust. The 
Carborundum Company was organized and the first plant 
estabhshed at Monongahela, Pa. In the first year 15,000 
pounds of carborundum were manufactured. This was in 
1893 ^^d two years later because of the great hydro-electric 
power plant that was being estabhshed at Niagara Falls 
the factory was moved there. Since that time the business 
of the company has grown until the present plant covers 
19 acres of floor space and is equipped to handle continu- 
ously 25,000 horse power of electric energy. Upwards of 
a milUon and a haK pounds of carborundum are manufac- 
tured every month. 

An analysis showed carborundum to be a compound of 
carbon and silicon. The furnace charge for its preparation 
consists of coke, sand, sawdust and common salt. The coke 
and sand are the essential ingredients, the sawdust being 
used to make the mass porous and the salt as a purifier. 
The furnace itself, built of fire brick, is 30 feet long, 12 feet 
vride and 10 feet high. The mixture is mounded up in the 
furnace and a resistance core built through the center. At 
each end are huge cables through which the current is 
conducted and passed along the core where it generates 
the vQYy high temperature of the electric furnace. The 
current flows for 36 hours and during this time enough 
electric energy is consumed ''to operate an arc Hght con- 
tinuously day and night for 12 years or to operate one 
sixteen-candle-power carbon incandescent lamp for 220 
years." There are 30 of these furnaces in continuous 
operation. 

At the end of the run the furnace is opened up and huge 
masses of beautiful carborundum crystals glistening with 
all the colors of the rainbow are removed. These crystals 



314 The Boys^ Own Book of Great Inventions 

are crushed, washed with strong acids and sieved through 
screens of bolting silk into grits of various sizes. Bonding 
material is added and the mixture is fashioned into grind- 
ing stones and wheels of all shapes and sizes, but this 
process is another story. These stones are good for grind- 
ing everything from jewels and teeth to railroad iron and 
armor plate. 

Here, too, in the Acheson plant artificial graphite excel- 
Hng the natural product of the nciines is manufactured in 
the intense heat of the electric furnace. 

Another electric furnace product manufactured at 
Niagara Falls and Worcester, Mass., is Alundum. This is 
the trade name of an artificial emery made by fusing alimi- 
inum oxide and rivals carbonmdmn as an abrasive. Under 
the influence of the electric furnace a large variety of other 
alundum products are manufactured for use in chemical 
laboratories and high temperature industries. Crucibles, 
combustion tubes and resistance furnace cores, unaffected 
by the most sudden and violent changes of temperature, 
have been of immense assistance to the chemist. Such 
ware may be heated white hot and plunged into ice water 
without breaking. 

The electric furnace is used, too, for the manufacture of 
calcium carbide, the fertilizer calciimi cyanamide, and for 
the highly important process of getting nitric acid from the 
air. Electric furnaces are employed in the metallurgy of 
steel, and a host of chemical industries depend for their 
success upon the high temperatures which electric energy 
will produce. 

One more application of the arc must be mentioned and 
that is in electric welding. The art of welding is as old as 
the working of metals itself. At Delhi, India, stands an 
iron shaft 16 inches in diameter, extending 22 feet above 



Fire and High Temperatures 315 

the ground and 40 feet below which shows a hand-forged 
weld as perfect as any that could be made with the most 
modem process and equipment. And this shaft is nearly 
two thousand years old. The electric-arc welding process 
as applied to broken street car rails is a frequent sight on 
our city streets. In the Slavianoff system, the most im- 
portant of arc welding processes, a metallic pencil serves 
as the negative electrode and the metal to be worked as the 
positive. One of the lead wires is joined to the pencil and 
the other to the metal to be welded. An arc is struck by 
bringing the two electrodes together and then quickly 
separating them. In the intense heat of the arc the metal 
melts and runs together into a soKd mass. Sometimes 
liUing-in metal is inserted between the broken ends. A 
protection from the fierce heat and bHnding Hght must be 
worn by the operator and great skill exercised in the manip- 
ulation of the arc. In many of the recently constructed 
shipyards no other welding process is employed. 

Oxy-acetylene Welding. — ^Another commercial process 
which must be credited to recent progress in high tempera- 
ture research is that of oxy-acetylene welding. When acety- 
lene gas is burned in a blowpipe similar in construction to 
the oxy-hydrogen blowpipe a flame results whose tempera- 
ture is very close to that of the electric furnace. With a 
torch of such temperature it at once became possible to weld 
the more difficultly fusible metals simply by melting them 
together. By this process metals of almost any kind can 
be welded, and wrought iron and steel can be cut with the 
utmost ease and perfection. If the metals are thin their 
edges are brought into contact at every point and then by 
application of the torch fused together. In other cases a 
space is left between the metals to be joined and the oper- 
ator holding the torch in one hand and a stick of the same 



3i6 The Boys' Own Book of Great Inventions 

kind of metal in the other, fuses it and runs it into the 
space. Previously to doing this, however, the metals to be 
welded are pre-heated so as to shorten the process and 
eliminate strains when the weld has cooled. 

This process has a large number of applications. It is 
especially adapted to repair work of all sorts. Steel tanks 
can be welded instead of riveted. It is employed on refrig- 
erating pipes, safes, steel office furniture, bicycle frames, 
aluminum ware, automobile parts and the results are 
permanent and highly satisfactory. In a skating rink in 
San Francisco more than ten thousand joints and ten 
miles of brine pipes were welded recently by the oxy-acety- 
lene process. 

But it is in the cutting of wrought iron and steel that the 
oxy-acetylene torch has had its most interesting appKca- 
tion. An especially constructed torch pre-heats the metal 
to be cut to a temperature of about 1000° C. by a number 
of small oxy-acetylene jets and then a jet of oxygen at high 
pressure is turned on. This oxidizes the hot metal and the 
force of the jet carries away the molten oxide as fast as it 
forms. Old armor plate that was formerly cut by the 
most laborious processes requiring weeks of time is now 
cut in little more than as many hours. Steel up to 30 
inches in thickness is readily cut. In one instance a gun- 
turret top was cut at a cost of $54.38 which by the old 
method of drilHng holes and breaking would have cost 

$2,CXX). 

It should be borne in mind, too, that these processes 
which save not only time and money but make possible 
scores of new achievements are the results of scientific 
research. It is to men like Davy, Faraday, Moissan and 
Edison, only to mention a few, that the world owes its 
marvelous material progress of to-day and recent years. 




Oxy-actylene, thermit and electric welding. 



Fire and High Temperatures 317 

Thermit Welding. — Still another source of high temper- 
atures and a process of very great commercial importance 
must claim our attention before we leave this subject. 

Go into the locomotive repair shops of any great railway 
terminal and there you will find men wearing large, colored 
glasses at work tapping white hot molten steel at a temper- 
ature of 5000^ Fahrenheit from a conical vessel into a sand 
mold built about the broken parts of some locomotive 
drive wheel or portion of the frame. These men are em- 
ploying the "thermit" process of welding and this disabled 
locomotive will be ready for service within twelve hours 
from the time it came into the shops. Furthermore, the 
•\velded part will be stronger than it was originally. In the 
"old days" it would have been necessary to remove the 
broken parts, forge and replace them, necessitating a delay 
of days and frequently weeks. But not so now, thanks 
to the marvelous progress of chemical research and in- 
vention. 

But what is thermit? The name suggests thermal, and 
the two words have the same basic meaning — heat. And 
that is the reason for the name, for the temperature gener- 
ated in this process is among the highest known to science. 
Soon after the production of pure alimiinum and the de- 
termination of its properties in 1854, it was discovered 
that, if this metal were heated with a metalHc oxide, a 
chemical change of explosive violence would take place, 
hberating immense quantities of heat and bHnding light, 
together with the molten metal at a temperature much 
higher than its melting point. Regarded at first as an 
interesting experiment, it remained for Dr. Hans Gold- 
schmidt to give a practical appKcation to this important 
chemical change. 

Just at that time Dr. Goldschmidt was attempting to 



3i8 The Boys^ Own Book of Great Inventions 

produce pure metals to alloy with iron in making various 
kinds of steel. Knowing this property of aluminum, he 
decided to make use of it and began to experiment. The 
explosive violence of the reaction first had to be overcome, 
and this was accompHshed by heating the mixture of 
aluminum dust and metallic oxide in a single spot until the 
change began, when it would spread quietly throughout 
the whole mass, liberating a lake of molten metal as clear 
and limpid as water in a cup. No one who has never ex- 
perienced it can have any adequate appreciation of the 
keen pleasure enjoyed by an investigator who thus carries 
to a successful termination some piece of research. Dr. 
Goldschmidt found that practically any metal could be 
obtained in this way, and among those with which he 
experimented was iron. The result was the production of 
the superheated, Hquid metal at nearly double the temper- 
ature of molten steel. The process required but 40 to 50 
seconds for completion, and Dr. Goldschmidt decided that 
such intense heat, so quickly and easily produced, could be 
used in many ways for welding purposes. This decision 
resulted in the ''thermit" process, soon so widely known 
throughout the world. 

Thermit itself consists of small, black grains of iron 
oxide thoroughly mixed with finer grains of alxmiinum 
dust. Were it not for the white particles it would have 
much the same appearance as coarse gunpowder, but no 
one would ever suspect the vast quantities of wonderful 
energy latent within. It is shipped in metal drums care- 
fully sealed to exclude moisture, for if it once becomes 
damp, the thermit is useless and cannot be regenerated by 
drying. Thermit is perfectly safe to store, for a temper- 
ature equal to that of molten steel is required to start the 
chemical reaction. 



Fire and High Temperatures 319 

In making a thermit weld, the parts to be united are 
placed with a space between them varying from one-half 
inch to two or three inches, according to the size of the 
sections. Wax is then fitted in this space, making a pattern 
of th€ exact shape of the reinforcement of the thermit 
steel, which is to be cast around the parts to make the 
weld. This wax pattern is enclosed in a sand mold, provi- 
sion being made for pouring and overflow openings at the 
top and a small opening at the bottom for preheating the 
parts to be welded. By means of a compressed air gasoline 
pre-heater the wax is melted from the mold and the parts 
brought to a good red, workable heat. In the meantime 
the requisite charge of thermit is placed in a conical cru- 
cible lined with a fireproof clay and the crucible placed 
over the pouring ''gate" of the sand mold. When the 
sections are red hot the pre-heater is withdrawn, the open- 
ing at the bottom plugged up and the thermit charge in the 
crucible is ignited. In from 40 to 50 seconds the thermit 
reaction is completed, and the thermit steel is tapped from 
the bottom of the crucible into the mold, where it flows 
around and between the sections to be welded together, 
uniting them into one soKd mass. The iron being heavy, 
sinks into the mold and the slag, consisting of aluminum 
oxide, rises to the top and overflows. A considerable 
quantity of iron also rises into the pouring and overflow 
gates and when soKdified projects above the welded part 
as so-called ''risers." To ignite the thermit in the crucible 
requires a very high initial temperature, and to obtain this 
an especially prepared powder is placed on the thermit, 
together with the head of a parlor match. When the 
match is ignited, this powder burns with such intense heat 
as to start the thermit reaction. 

The welded portion is allowed to cool slowly, for this 



320 The Boys^ Own Book of Great Inventions 

anneaKng process removes strains and increases the strength 
of the weld. The next step is to cut away the risers and 
machine off the surplus metal. When this has been done, 
the welded shaft or whatever it may be is not only repaired 
but is actually stronger than before it was broken. In- 
stead of being a weak spot and source of further trouble, it 
is in fact an added element of strength. 

One of the most extensive uses of thermit is in the ma- 
rine field for welding broken sternposts, rudder frames, 
and propeller shafts of steamships. The great economy in 
this field can easily be understood, from the fact that the 
average cost to a steamship of lying in dry dock is $i,ooo 
a day, and therefore if a repair can be executed in 48 hours 
by this process, as against several weeks by the former 
methods, a tremendous saving is effected. The United 
States Navy v/as among the first to appreciate the advan- 
tage of the thermit process and has used it very extensively 
at the New York, Boston, Portsmouth and Charlestown 
navy yards. In addition, the repair ships Panther, Dixie, 
and Vestal have complete thermit welding outfits and have 
done very :'mportant work. 

Vast quantities of thermit have been used by the Gov- 
ernment on the Panama Canal, and the process has been 
employed for welding and reclaiming broken parts of 
dredges, dipper buckets, locomotives, rock crushers, rock 
driUs, air compressors and all sorts of machinery used in 
building the canal. 

But one of the most striking and familiar applications 
of the thermit process has been by street railway companies 
in welding broken rails and installing permanent joints in 
place of mechanical joints. Scenes similar to those in the 
accompanying picture are frequent sights along the street 
railway lines of any large city. 



Fire and High Temperatures 



321 



HIGH TEMPERATURE EXPERIMENTS 

I. A Homemade Electric Furnace. — An electric furnace of 
the arc type can very easily be made by any boy from the 
following materials: fire clay, asbestos fiber and water 
glass. A mixture of these ingredients will quickly dry and 
harden into a fireproof mass of low heat conductivity. 

To make the furnace, select a box about 8 inches long and 
4 inches square. Bore a hole a little above the center of 















PIN 


TUMBLER 


1 






PIN 














MIXTURE 





ELECTRIC FURNACE 
Fig. 96. — ^Arc furnace. 

each end just large enough to take a standard light carbon. 
Then mix some of the fire clay, asbestos fiber and water 
glass, in the form of a solution, until a doughy mass is 
obtained, and pack a layer one inch thick in the bottom of 
the box, forcing it down as far as possible. Now insert an 
ordinary glass tumbler in the center of the box and two 
wooden pins the size of light carbons in the holes at the 
ends. Around these pack as firmly as possible more of the 



322 The Boys^ Own Book of Great Inventions 

mixture, filling the box completely. Smooth off the top 
and fill in the small cavities with a mixture of fire clay and 
water glass alone. In similar manner make a cover of the 
same size about an inch thick. Place the box and contents 
together with the cover in some warm place, preferably on 
the top of a furnace, and allow them to dry for about ten 
days. At the end of that time the box may be broken 
away and the pins and tumbler removed. To improve its 
appearance the outside may be retouched with a little fire 
clay and water glass. The result is a very efficient arc 
furnace of practically indestructible material which can be 
used in series with a suitable resistance on any house Kght- 
ing circuit for many experiments where high temperatures 
are required. The materials, too, are inexpensive and easy 
to obtain. 

A small carbon crucible containing any substance which 
it is desired to heat may be placed just beneath the carbons. 
For this purpose it is a good plan to make the holes for the 
carbons slanting downward into the cavity. 

2. A Resistance Furnace. — ^Another type of furnace owing 
its heat-producing power to the resistance of a metallic 
conductor will be found very useful. To make it, secure 
a corrugated Alundimi core 2}4 inches deep and 2 inches in 
diameter. This is hollow and should be closed at one end 
and open at the other. Now wind as closely as possible 42 
feet of No. 20 Nichrome wire on a spindle ^/s2 of an inch in 
diameter, leaving one foot free at each end for connections. 
When it has set stretch the coil sKghtly so that the turns 
will not touch, and starting with one end at the center of 
the grooves on the bottom of the core wind it about the 
cylinder and secure it in position temporarily with cord. 
Cover the whole with a layer of Alundum cement to a 
depth of Vs of 2,n inch and connect directly to a no volt 



Fire and High Temperatures 323 

lighting circuit. This will very quickly cause the cement 
to set. 

This furnace will give a continuous temperature of 1000° 
C. For lower temperatures a rheostat must be inserted in 
series with the furnace. 

A cover like that of the arc furnace should be made of 




--OPEfM tND 



.APPEARANCE OF nJRNACE DEIFORE COVERING 

WITH ICEMELNT 

Fig. 97. Resistance furnace. 

asbestos fiber, fire clay and water glass. When in use 
always set the furnace on a square of asbestos cardboard. 

3. Melting Metals. — In a porcelain crucible place a few 
pieces of metallic copper and set the crucible in the furnace. 
Cover and use the full no volts of the lighting circuit 
without the rheostat. Usually the melting point of copper 
will be reached. 

4. Making Quicklime. — Place a few lumps of marble in 
the furnace and heat for 20 or 30 minutes. After the cur- 
rent has been turned off and the product is thoroughly cold 
remove some of it and sprinkle with a Httle water. This is 



324 



The Boys^ Own Book of Great Inventions 



quicklime, and the swelling up and evidences of heat ob- 
served are the same as occur in the slaking of lime in a 
mortar box on the street. Your furnace is a miniature 
limekiln. 

Other uses for the furnace will suggest themselves. If 
you have a laboratory, for much work it will take the 
place of a Bunsen burner. 



MAGNEisiuM (Gibbon 

" OUST. 
THERMIT 




V 



SHEET IRON. 



.^AND. 



=0 



Fig. 98. — ^Thermit demonstration. 

5. Demonstration with Homemade Thermit. — ^A very strik- 
ing and spectacular demonstration with homemade "ther- 
mit" can be carried out by anyone with the following 
materials and directions: 

Mix about equal quantities of alimiinum dust and red 
iron oxide, or ordinary rouge, on a folded paper and place 
the mixture over a battery jar of water as shown in the 



Fire and High Temperatures 325 

diagram. Prepare the paper by cutting a circular piece 
about 3>^ inches in diameter, folding in half and then 
folding in half again, when it may be opened up in the form 
of a hollow cone which will serve as a container for the 
thermit. At the top of the conical heap of thermit place a 
little magnesium dust and thrust into it an inch and a half 
strip of magnesium ribbon. The bottom of the battery 
jar should contain an inch layer of sand on which place a 
tripod, or some other support carrying a square of sheet 
iron. The square of iron may be three or four inches be- 
low the surface of the water. Upon touching a match to 
the magnesium ribbon the whole mass of thermit will 
quickly ignite and a stream of white hot molten iron will 
run into the water and striking the sheet iron melt a hole 
through it. If the demonstration is made in the evening or 
in a darkened room a very brilliant effect is produced. 

The chemical action consists in the union of the alimi- 
inum with the oxygen of the iron oxide, liberating the iron 
and an immense amount of heat energy. This is the same 
reaction that occurs in the thermit process of welding a 
broken street car rail. 

The ignition powder will work better and more certainly 
if a little powdered potassium chlorate is mixed with the 
magnesium dust. 



Chapter XVII 

SOME NOTABLE ACHIEVEMENTS IN 
CHEMISTRY 

The War of the Nations which at the present moment 
has been raging for four years, is in its physical and mate- 
rial aspects a tremendous contest between chemical forces. 
From the poisonous gases, the high explosives, the armor 
plate and the big guns to the healing drugs of the hospital 
and the fertilizers for the production of food stuffs, it is all 
a matter of chemistry. Every volley that sweeps the 
shell-torn battlefields of Europe is accompanied by a million 
chemical reactions. And what havoc this rnad dance of the 
atoms and the molecules has wrought. Such violent Hber- 
ation of pent up chemical energy has at last created the 
madman's paradise. Even the inventors of explosives 
have surprised themselves. Before the terrific onslaught 
of T. N. T. concrete and steel are as chaff in the wind. The 
fixed fortress has become obsolete. The strongest walls 
can be reduced to ruins in a few hours. In the volcanic- 
Hke breath of a bursting shell a thousand Hves may be 
snuffed out and the adjacent scenery blown to dust. Mod- 
em warfare is the product of the man of science. The 
cannon-fodder on the battlefield is merely a huge mech- 
anism to execute his will and give practical demonstration 
to the creations of the laboratory. Without Germany's 
chemists this war would have been over in a few weeks, or 
months at the most. In fact, it never would have been 
begun. It is the Krupp steel works, the nitrate-from-the- 

326 



Some Notable Achievements in Chemistry 327 

air plants, the early monoply of coal tar explosives that the 
world has had to fight. They afforded the sinews for 
Germany's murderous attack on the peace of Europe. 
More to be dreaded than her armies are the scientists in 
her laboratories. But although the rest of the world was 
caught napping, the men of science in other nations have 
demonstrated their abihty to specialize in the chemistry 
of war and beat Germany in her own chosen field. 

Explosives. — Since the foundations of the earth are 
fairly rocking from the liberated energy of high explosives, 
let us first consider this aspect of modern chemistry. From 
the black gunpowder of a century ago to the nitrocellulose, 
picric acid and T. N. T. of present-day warfare, nitric acid 
has been an essential ingredient of their manufacture. 
And therefore the matter of explosives comes down to a 
question of producing in abundance this nitrogen com- 
pound. Old-fashioned gunpowder was a mixture of pow- 
dered charcoal, sulphur and potassium nitrate, or saltpeter. 
Napoleon scraped together the saltpeter for his campaigns 
from caves and decaying compost heaps. But he did not 
need very much. More nitrates are used in one day's 
cannonading on the Western Front than Napoleon or 
Grant used in a whole campaign. Nitrates are salts of 
nitric acid and essential to the production of the acid. In 
only one spot on the earth's surface is nitrate salt found in 
abundance. This is a narrow rainless strip on the western 
slope of the Andes mountains in northern Chili. These 
deposits are known to the world as Chili saltpeter. They 
have been and are yet of immense importance as soil ferti- 
lizer and for the manufacture of explosives. For many 
years they constituted the world's sole supply. Previously 
to the war they were being exported from Chili at the rate 
of nearly 2,000,000 tons a year. As one slight preKminary 



328 The Boys^ Own Book of Great Inventions 

item of preparation for her great attack, Germany in the 
year before the war corralled 1,000,000 tons of these salts. 
She also bought all that were available in the markets of 
Europe. But when the titanic struggle burst forth even 
this immense store disappeared like mist before the sun. 
When it became apparent that Germany had something 
more on her hands than a brilliant military parade for the 
overawing of Europe, other means for the manufacture of 
nitric acid were at once imperative. Her initial supply was 
only a priming. But Germany was prepared for any emerg- 
ency. Her chemists had solved this problem before the 
war was launched. They even announced it to the world 
at the meeting of the International Congress of AppKed 
Chemistry held in New York in September, 191 2. In 19 13 
Germany was investing millions of dollars in chemical 
plants for this very purpose. She is now using over 200,000 
tons of nitric acid each year and, though cut off from the 
outside world, her supply is inexhaustible. 

Before we take up the present war-time process em- 
ployed by Germany' for making nitric acid we miist go 
very briefly into the history of the *' fixation" of atmos- 
pheric nitrogen. Nitrogen is a most inactive element. It 
enters into chemical combination with other elements with 
great difficulty. And yet it is most essential to Kfe and 
industry. Not only is it the moving factor in high explo- 
sives, but it is also a fundamental ingredient of a complete 
fertilizer and a constituent of all tissue-building foods. 
Therefore, when Sir William Crookes in 1898 in his presi- 
dential address before the British Association for the 
Advancement of Science predicted the early exhaustion of 
the Chili nitrate beds and urged immediate work upon a 
process for fixing into available compounds the inexhaust- 
ible supply of nitrogen in the air, the chemists of the world 



Some Notable Achievements in Chemistry 329 

got into action. It was also seen that any nation cut off 
from Chili saltpeter in time of war would be powerless to 
resist and forced to surrender. Therefore the spur of 
self-preservation acting from opposite points of the com- 
pass prompted widespread and vigorous research on this 
problem. 

The great ocean of atmosphere about us is four-fifths 
free nitrogen. Upon every square yard of the earth's 
surface rests approximately seven tons of this element. 
But how to make it combine with other elements into 
useful compounds was a baffing problem. The first men 
to work out a practical solution were two Americans, 
Bradley and Lovejoy. In 1902 at Niagara Falls they 
established the first commercial process for the fixation of 
atmospheric nitrogen by means of the electric arc. They 
demonstrated the possibility of making nitric acid in pay- 
ing quantities directly from the air, but both the capitalists 
and the Government were indifferent and its development 
passed to other countries. At the same time other inves- 
tigators were at work and very soon it was announced 
from Norway that Birkeland and Eyde had also solved the 
problem. They, too, employed the electric arc, using a 
high-tension alternating current and water-cooled copper 
electrodes. Air was passed through this arc and it was 
placed between the poles of a powerful electro-magnet 
which blew it out into a flaming disk of burning nitrogen 
and oxygen. In the intense heat of this arc nitric oxide is 
formed which unites with more oxygen from the air to 
form nitrogen peroxide, and this dissolved in water yields 
a mixture of nitric and nitrous acids. Other processes also 
employing the electric arc were developed in Germany. 
Still another process has been perfected whereby in the 
heat of the electric furnace free nitrogen obtained from 



^7,0 The Boys^ Own Book of Great Inventions 

liquid air can be made to combine with calciimi carbide 
and form the highly important fertilizer, calcium cyana- 
mide. 

At last the world seemed independent of Chili saltpeter. 
Millions of dollars and hundreds of thousands of horse 
power were soon engaged in the profitable business of 
extracting nitrogen from the air. But there was one draw- 
back to these new-found processes. They depended for 
their success on vast quantities of cheap electric energy, 
and this is possible only where there is an abundance of 
water power. The immense water power in the mountains 
of Norway made that country especially adapted to the 
installation of these nitrogen-from-the-air-plants and there 
they have had their greatest growth. The waterfalls and 
rivers of Norway have a potential capacity of 2cx),ooo,ooo 
horse power, and this region is destined to become one of 
the greatest industrial centers of the world. Iceland, 
Africa and America also have great water power, all of 
which must and will be turned to account. But Germany 
is lacking in this prime requisite and her coal is needed for 
other purposes. Therefore in her case some other method 
for making nitric acid was a necessity. 

From the beginning of the coal gas industry a century 
ago these plants have been busy extracting the ammonia 
from the gas. Ammonia is another nitrogen compound 
famihar as a household cleaning agent and characterized 
by a sharp penetrating action on the nostrils, making it 
useful in the emergency of a hard cold. Although bought 
in the form of a liquid, ammonia is a gas and the familiar 
household variety is the gas dissolved in water. Ammonia 
is also used for laboratory purposes, for the manufacture 
of artificial ice and for the production of ammonium sul- 
phate, an important commercial fertilizer. The coke 



Some Notable Achievements in Chemistry 331 

industry, which is simply another phase of gas manufac- 
ture, also yields ammonia. 

Now just previously to the Great War a German chemist 
named Haber devised a process for making ammonia directly 
from the two elements which compose it, namely, nitrogen 
and hydrogen. Then to supplement this the famous Ger- 
man chemist Ostwald had perfected another process for 
oxidizing the ammonia into nitric acid. To develop these 
processes years of research were required and numerous 
difhculties had to be overcome. If the supply of ammonia 
from the coke and gas industries were sufficient the Haber 
process would be unnecessary, but there are so many other 
essential uses for this valuable product that it cannot be 
spared for the manufacture of nitric acid. Both of these 
processes are catalytic, that is, they are brought about and 
made possible through the influence of a third substance 
which greatly hastens the chemical changes taking place. 
Haber's method consists in passing nitrogen and hydrogen 
gases at 200 atmospheres pressure and 1300° Fahr. over 
finely divided uraniimi metal. For this purpose the gases 
must be exceedingly pure or the uranium catalyst will 
become ''poisoned" and cease to act. The nitrogen is 
prepared from boiling liquid air. At ordinary pressure and 
a temperature of — 190° C. the nitrogen boils off, leaving 
the oxygen. The hydrogen is made in a similar manner 
from ''water gas" or is obtained from the electrolysis of a 
solution of caustic potash. Ostwald's process for the 
oxidation of ammonia to nitric acid consists in passing the 
gas mixed with air over heated platinum gauze. The 
oxygen in the air unites with the ammonia to form nitric 
acid and water. Great quantities of electric energy are 
not required in these processes and the raw materials used 
are inexhaustible. By their perfection Germany has made 



332 The Boys^ Own Book of Great Inventions 

herself absolutely independent of outside assistance for the 
manufacture of high explosives. As far as this factor is 
concerned she might continue the war indefinitely. But 
she did not dare to start this war until these processes had 
been invented and preparations for their appKcation were 
complete. Considering the gigantic conflict which all these 
inventions have made possible, do you wonder that the 
fixation of atmospheric nitrogen has been pronounced the 
greatest achievement in applied chemistry of the last 
quarter of a century? 

The United States Government in 19 15 appropriated 
$20,000,000 for the construction of a nitrogen-from-the- 
air-plant and doubtless since the beginning of the war 
other steps in this direction have been taken. No excuse 
now remains for any nation to be deficient in the means of 
producing in abundance this fundamental requisite of 
self-defense and modern warfare. 

From the battle of Cressy until the second haK of the 
nineteenth century no great advance was made in the 
manufacture of explosives. Black gunpowder was still 
used. Then came nitroglycerin, the first of the modern 
high explosives. It is made by treating ordinary glycerin 
with a mixture of concentrated nitric and sulphuric acids. 
Three nitro-groups from the acid unite with the glycerin 
and a Hquid product very closely resembhng the original 
glycerin results. Its very great explosive violence is due 
to the fact that the molecule of nitroglycerin contains 
within itself the oxygen necessary for its own combustion. 
In old-fashioned gunpowder we have the carbon, sulphur 
and saltpeter in separate particles. The oxygen for burn- 
ing the carbon must come from the saltpeter, outside itself, 
and therefore the combustion is comparatively slow. If 
gunpowder is to be used for blasting rocks a hole must be 



Some Notable Achievements in Chemistry 333 

drilled and the powder tamped down to confine it. If 
unconfined, gunpowder will burn quietly without explosion 
or danger. But if nitroglycerin is simply placed on a rock 
its explosion will shatter the rock into a thousand fragments. 
The greatest force from nitroglycerin is exerted in the di- 
rection of the points of contact with it. Unmixed with other 
explosives it is useless for firing projectiles, for its explosion 
will shatter the gun itself. Nitroglycerin is not particularly 
easy to explode. It requires a certain sympathetic vibration 
imparted by a fulminate of mercury cartridge. Of course 
it may get this shock in other ways, and it is treacherous 
stuff to handle. When frozen it expands like ice and is more 
sensitive to percussion than when in the Hquid state. It is 
very easy to make nitroglycerin in the laboratory, but un- 
less you are contemplating suicide it is a dangerous pastime. 

Alfred Nobel, a famous Swedish chemist, was the first to 
manufacture nitroglycerin in quantity. But he could 
not get transportation companies to handle it for him and 
was about to give up the business, when one day he ob- 
served that some of the stuff which had leaked from a 
broken can had been entirely absorbed by the sand in 
which it was packed. This gave him the idea of making 
dynamite, which is both safer to handle and less violent 
in its action. 

The glycerin for this purpose was formerly obtained as 
a by-product of soap manufacture, but now so important 
has the explosive become that glycerin is the main product 
and soap the by-product. 

Nitroglycerin and dynamite have been of immense 
importance in mining operations, the tunneling of moun- 
tains, the shooting of oil wells and such engineering works 
as the Panama Canal. Without them much of this work 
would have been impossible. 



334 The Boys^ Own Book of Great Inventions 

Another violent explosive somewhat similar in compo- 
sition and preparation to nitroglycerin is gun cotton, or 
nitrocellulose. This is made by immersing purified cotton 
fiber in a mixture of concentrated nitric and sulphuric 
acids. In a few minutes it is removed, the excess of acid 
is pressed out and it stands for 24 hours for the process of 
nitration to take place. After washing and drying it is 
dissolved in a mixture of alcohol and ether, which converts 
it into a plastic mass suitable for molding and cutting into 
rods and grains of the proper size. This constitutes smoke- 
less gunpowder. It does not readily explode and if ignited 
in the open will simply flash and disappear. In 1878 Alfred 
Nobel discovered that instead of using alcohol and ether 
for the absorption of gun cotton, nitroglycerin could be 
substituted. The result was a mixture of the two most 
violent explosives known to science. Nobel caUed it 
^' cordite^' and it proved to be an ideal ammunition for 
guns. 

Picric Acid, about which we have heard so much during 
the war, is a yellow crystalline solid made from carbolic 
acid by treating with nitric and sulphuric acids. It, too, 
is a violent explosive used in making shells which liberate 
large quantities of poisonous gases when they burst. 

The explosive, however, that has made the strongest 
appeal to the popular unagination is T. N. T. or trinitro- 
toluol. The starting point for this is toluol, one of the 
chief products of coal tar. This, too, is a mass of yellow 
crystals and a very "safe" explosive. It can be ignited, 
pounded with a hammer, riddled with bullets and sub- 
jected to all sorts of rough usage without danger of explo- 
sion. But when it gets that particular sympathetic vibra- 
tion from a fulminate of mercury cap, there begins the 
wild dance of the atoms and before they recover their 



Some Notable Achievements in Chemistry 335 

equilibrium the projectile against which they pushed has 
sped ten miles on its mission of destruction and death. 
Shells loaded with 500 pounds of T. N. T. are in common 
use, and the awful havoc wrought on both sides of the 
Western Front and elsewhere in the war zones of Europe 
is the best evidence of the vast quantities of energy stored 
within. 

Thus the consideration of high explosives shows how the 
World War had to wait for the chemists to get ready. But 
we must not forget that explosives and their destruction 
are mere incidents in the achievements of modern chem- 
istry. Chemists in general cannot be held accountable if 
mad despots turn their discoveries into instruments of 
annihilation. The main purpose of chemistry is to discover 
nature's secrets and thereby bring the peaceful industries 
of the earth to a higher degree of perfection. But so com- 
plex and interwoven are the industries and instruments 
essential both to peace and war that any real progress may 
be turned in either direction. 

The Coal Tar Industry. — It is not so many years ago 
that coal tar had no more important use than to keep the 
crows from pulling the corn in the farmer's fields. Dirty, 
black, foul smelling stuff, it was regarded as an unmitigated 
nuisance and for a hundred years was treated as pure 
waste. To-day it is probably the most valuable single 
by-product of chemical manufacture. It is a tremendous 
resource both of peace and war. From it we draw the 
explosive that wounds the soldier and the healing drug 
that effects a cure. Like a magician the chemist makes 
this imsightly mass yield all the brilliant hues of modem 
dyestuffs. He pulls out of it the most dehcate perfumes 
known to nature. Here the physician finds an inexhaust- 
ible storehouse of powerful drugs for the stilling of pain, 



33^ The Boys^ Own Book of Great Inventions 

the allaying of fever and antiseptic uses. The connoisseur 
of sweets finds a compound five hundred times sweeter 
than any sugar. Chemicals for the prevention of vegetable 
decay and pitch for paving and roofing are useful by- 
products. 

Coal tar is a by-product of the coke and gas industries. 
To make either coke or gas, soft coal is heated in closed 
retorts out of contact with the air. This process is called 
*' destructive distillation." The gaseous matter driven 
from the coal is first made to pass through a 3 -foot pipe 
called the hydraulic main in which the coal tar is extracted, 
and it is then passed on to the scrubber where the arnmonia 
is removed. For many years and until very recently in 
this country so-called beehive coke ovens were employed 
for this purpose and all the gas, coal tar and ammonia 
allowed to burn as they escaped. In this way $75,000,000 
worth of by-products went up in smoke each year. But the 
coke obtained from these ovens was used in the smelting 
of iron ore and nothing else was desired. It was an expen- 
sive process to install the modern by-product coke oven 
and "cheaper" to allow Germany to supply us with the 
necessary dyestuffs and other coal tar products. Our 
capital could find more profitable employment in other 
ways. Besides, we imported only about $10,000,000 worth 
of these products each year, and such a small item was not 
considered worth bothering with. The fact that the textile 
industry, the manufacturers of inks, paints and stains and 
all other industries using colors in any way were dependent 
upon Germany for their dyestuffs was not taken into 
account. As a result, when the war broke out there was an 
immediate dyestuff famine in every country of the world 
outside of Germany. Colors could not be had to dye the 
uniforms of the soldiers. Even our own Government had 



Some Notable Achievements in Chemistry 337 

to beg Germany for enough dyes to color our stamps and 
paper money and to get permission to bring them over in 
Dutch ships. But happily this has passed and the United 
States now possesses a dyestuff industry which only the 
indifference of Congress will ever allow to be displaced by 
German competition. 

The dyestuff industry and the beginning of the coal tar 
romance had its origin in the research work of a mere boy. 
In 1856 Sir William Perkin, then a lad of seventeen, was at 
work in his private laboratory endeavoring to extract the 
drug quinine from coal tar. One day as he added alcohol 
to a dirty, black mass that had precipitated in his beaker, 
there appeared a brilliant purple color. This was mauve, 
the first of a host of aniline dyes. He extracted the stuff 
and so contagious was his enthusiasm that he persuaded 
his father and brother to set up a factory for its manufac- 
ture. With no previous experience in chemical industries, 
he overcame all obstacles and placed his product on the 
market. A few years later from another coal tar derivative, 
he extracted alizarin, the brilliant ''turkey red," which for 
many years had been obtained from the madder plant. 
That event sounded the death knell of the madder plant 
industry. News of these discoveries spread throughout 
Europe and the chemists in other countries went to work, 
particularly in Germany. The production of gorgeous 
colors of every hue followed each other in rapid succession. 
Dye works sprang up everywhere. But the British govern- 
ment, giving no encouragement to the industry, it passed 
largely under German control. 

For centuries indigo had been obtained from the indigo 
plant. The Egyptian mummies are found wrapped in 
clothes dipped in this ancient dyestuS- But in 1879 a 
famous German chemist, Adolph von Baeyer, produced 



338 The Boys^ Own Book of Great Inventions 

indigo artificially from coal tar products. The dye plant 
of the Badische Anilin und Soda Fabrik then took up the 
problem and after fifteen years of exhaustive research and 
the expenditure of millions of dollars, S3nithetic indigo at 
a few cents a pound became a fact. The value of the an- 
nual product of the indigo planters quickly dropped from 
$20,000,000 to $300,000. A brilliant array of red, yellow 
and green derivatives of indigo have also recently been 
obtained. 

Now nearly 2,000 coal tar dyestuffs are known. They 
cover every shade and hue and meet every requirement of 
taste and fashion. Millions of capital and thousands of 
men are engaged in the industry. Not only do these plants 
produce dyestuffs but all the other species of the numerous 
tribes of coal tar products. During the war the German 
plants have directed their energies largely toward the 
production of medicines and explosives. They constitute 
one of the great war-making assets of the nation. But 
under the spur of four years of necessity, the other nations 
of the earth have become independent of Germany, and 
never again will she regain the immense monopoly of the 
coal tar trade that she enjoyed before the war. 

The By-Product Coke Ovens. — ^At the beginning of the 
war there were in this country comparatively few by- 
product recovery plants. By the summer of 1915, so great 
was the demand for these products in the munition fac- 
tories that the price of benzol had gone to 80 cents a gallon 
and that of toluol to $7 a gallon. Under such stimulus the 
number of these plants increased until on January ist, 
19 18, there were in operation in this country and Canada 
nearly 10,000 recovery ovens. In the old wasteful beehive 
oven not only were the coal tar, gas and ammonia lost, 
but for every ton of coke produced 200 pounds of coal 



Some Notable Achievements in Chemistry 339 

were needlessly burned in the process. Converting the 
combustible portion of these products (all save ammonia) 
into their equivalent value in pounds of coal and adding 
the 200 pounds needlessly burned, it is found that out of 
every ton of coal coked 825 pounds were lost. Rather a 
wasteful process considering the great fuel shortages that 
have been experienced. It might be said, however, that 
there is an abundance of coal in America for centuries to 
come and shortages have been due solely to unprecedented 
demands and lack of labor and transportation facihties. 

The ovens now in operation carbonize approximately 
47,400,000 tons of coal per year yielding 35,000,000 tons of 
coke, the balance being converted into coal tar, ammonia, 
gas and benzol oils. These figures do not include the nu- 
merous city gas plants which also produce similar products. 
Here is an economy forced upon the nation by the war 
that would have required a quarter of a century and more 
of peace time progress to effect. 

In the old by-product ovens the bulk of the benzol, 
toluol and xylol together with considerable quantities of 
napthalene were left in the gas. These substances en- 
riched the gas and for purposes of illumination were de- 
sirable, but with the modern gas mantle wholly needless 
and pure waste. Therefore, the modern ovens have added 
benzol recovery towers in which the gas is scrubbed with 
solvent oils. Formerly the supply of benzol, toluol, etc., 
all came from the fractional distillation of the coal tar, 
but now 95% of it is recovered from the gas. If all the 
coke required by this country were coked in by-product 
ovens having benzol recovery equipment, it is estimated 
that 110,000,000 gallons of benzol would be obtained each 
year. When it is understood, too, that benzol can be used 
in automobile engines with an increase of 20 per cent per 



340 The Boys* Own Book of Great Inventions 

gallon in mileage, we shall better appreciate what this 
recovery means to the nation. Before the war Germany 
used 50 per cent of her benzol in internal combustion 
engines. 

In addition, benzol is the starting point in the manufac- 
ture of aniline oil and the host of dyestuffs from it. Car- 
bolic acid, formerly distilled entirely from coal tar, is now 
made largely from benzol. Benzol is used in the manufac- 
ture of paints, stains and varnishes; for cleaning purposes; 
as a solvent for grease, fats and rubber and in the manu- 
facture of artificial leather. Toluol with nitric and sul- 
phuric acids gives the powerful explosive trinitrotoluol 
and is used in the production of such substances as sac- 
charin and benzoic acid. Saccharin is the compound 500 
times sweeter than sugar. 

The most of the ammonia recovered in these plants is 
passed into sulphuric acid and is converted into the im- 
portant fertilizer, ammonium sulphate. Some of it is 
dissolved in water for laboratory and household purposes 
and some is used for the manufacture of artificial ice. If 
necessity required ammonia might be oxidized to nitric 
acid by Ostwald's process. 

The bulk of the coke is used to reduce iron ore in the 
blast furnaces of the country. It is nearly pure carbon and 
its combustion produces intense heat. 

Only a small portion of recent chemical progress has 
been given in the foregoing paragraphs. But it would be 
difficult to find any industry of importance that does not 
have its chemical problems and nowadays its laboratory 
and staff of trained chemists. As the late Robert Kennedy 
Duncan said, the world is learning the difference ^'between 
the sway of the finger of Science and the ancient Rule of 
Thumb." 



Some Notable Achievements in Chemistry 



341 



SOME CHEMISTRY EXPERIMENTS 

I. Gunpowder. — To prepare old-fashioned gunpowder, 
mix thoroughly 30 grams of finely powdered potassium 
nitrate with 5 grams each of powdered charcoal and flowers 
of sulphur. 

Place the mixture on a square of asbestos and ignite 
with a long wax taper. 




Fig. 99. — Preparation of nitric acid. 

If thoroughly dry, finely powdered sodium nitrate, Chili 
saltpeter, may be substituted for the potassium nitrate. 

2. Preparation of Nitric Acid. — ^Arrange a ring stand, 
tubulated retort and condensing flask as shown in Fig. 99. 
Place in the retort about 15 grams of sodium nitrate and 



342 The Boys^ Own Book of Great Inventions 

by means of a funnel pour into it lo cubic centimeters of 
concentrated sulphuric acid. Insert the stopper in the 
retort and heat the mixture very gently, using a snriall 
flame. 

Very soon small drops of the acid will be seen condensing 
in the neck of the retort and trickling down into the flask. 
In the heating of the retort so far as possible avoid decom- 
posing the acid. If brown fumes appear remove the flame 
for a few moments. Continue the process as long as any 
nitric acid distils over. 

The liquid collected in the flask is very strong nitric acid 
and great care must be observed in handling it. 

To show its oxidizing action pour a very little in the 
bottom of a test tube and just above it place a loose plug 
of boiler felt or excelsior. Then holding the test tube with 
a holder heat the acid until it boils. As its hot vapor comes 
in contact with the boiler felt or excelsior the latter wiU 
take fire and burn vigorously. 

It is this oxidizing action of nitric acid that makes it 
valuable in the manufacture of explosives. 

The solvent action of nitric acid on metals can be shown 
by pouring a little on a small piece of copper in the bottom 
of a test tube and then adding a few drops of water. The 
brown fumes that come off are nitrogen peroxide. 

Nitric acid is the best general solvent for metals. 

Another experiment to show the oxidizing action of nitric 
acid can be carried out as follows: 

In the bottom of a test tube place a little sodium nitrate 
and cover with concentrated sulphuric acid. Heat in the 
Bunsen flame, holding the test tube with a holder, and when 
the vapor of nitric acid is coming off rapidly, thrust into it 
a glowing spHnt. The splint will immediately burst into 
flame. It is best to hold the spHnt with pincers or tongs. 



Some Notable Achievements in Chemistry 343 

3. A Flash Powder. — Mix equal parts of powdered 
potassium chlorate and magnesium powder. Place the 
mixture on an asbestos square and ignite with a long wax 
taper. Do not try to light it with a match. An instan- 
taneous flash of dazzling brilliancy results. 

Here, too, we have oxidation. The potassium chlorate 
contains three atoms of oxygen in each molecule which it 
very readily gives up to the magnesium. This mixture is 
used in many flash light powders for photography work. 

4. Red Fire. — Finely powder i gram of potassium chlo- 
rate and II grams of strontium nitrate separately. {They 
must not be powdered together.) Then make a mixture of 
the chlorate and nitrate together with four grams of flowers 
of sulphur and }i gram of lampblack. Place the mixture 
on an asbestos cardboard and ignite with a long taper. 
An intensely red flame results. 

For ignition purposes touch paper is useful. It is made 
by soaking unsized paper in a saturated solution of potas- 
sium nitrate and drying. It will burn like the fuse of a 
firecracker and cannot be extinguished by blowing. 

5. Green Fire. — Mix as before 3 grams of finely powdered 
potassium chlorate, 8 grams of finely powdered barium 
nitrate and 3 grams of flowers of sulphur. Place the mix- 
ture on asbestos cardboard or paper and ignite with taper 
or a short fuse of touch paper. To use touch paper make 
a conical heap of the mixture and insert a strip of the paper 
in the top. 

6. Purple Fire. — Finely powder and mix 2 grams of 
copper sulphate, 2>^ grams of flowers of sulphur and 15 
grams of potassium chlorate. Ignite on asbestos with 
touch paper or taper. 

For pulverizing substances a small earthenware mortar 
and pestle are essential. 



344 



The Boys^ Own Book of Great Invertions 



7. Nitric Oxide and Nitrogen Peroxide. — These com- 
pounds are intermediate products in the manufacture of 
nitric acid from the air. 

Arrange apparatus as shown in Fig. 100. The generator 
may consist of a wide-mouthed bottle into which is fitted 
a two-holed rubber stopper carrying a thistle tube and 
bent glass tube. The thistle tube must reach to the bot- 
tom of the bottle. Fill a basin about haK full of water and 
invert in it a bottle filled with water. To the bent glass 

tube connect a 15-inch 
length of rubber tubing, 
to the opposite end of 
which is fitted a glass 
deHvery tube. 

In the generator put 
a few copper rivets and 
just cover with water. 
Add about a third as 
much concentrated ni- 
tric acid and wait for 
the action to start. 
Don't grow impatient, 
for the action will be 
vigorous enough when it 
does come. Sometimes it is necessary to add a Httle more 
acid. If the action becomes too vigorous, slow it down by 
adding water. (Pour both acid and water through the 
thistle tube.) 

When the action starts, place the dehvery tube beneath 
the inverted bottle and allow the gas to displace the water. 
Two bottles of the gas may be collected if desired. When 
the bottles are full stop the action by pouring water through 
the thistle tube. 




Fig. 100. — ^Preparation of nitric oxide. 



Some Notable Achievements in Chemistry 



345 



It will be noted that the gas in the bottle is colorless. 
This is nitric oxide. It is also insoluble in water, for if it 
were soluble the water would rise in the bottle. 

Now lift one of the bottles from the water and the gas 
immediately turns reddish brown. (Do not breathe the 
fume's.) The nitric oxide has taken on oxygen from the 
air and formed nitrogen peroxide. 

Now place the bottle mouth downward in the water and 
the water will immediately rise in the bottle, the brown 
color disappearing at the same 
time. The nitrogen peroxide 
has dissolved in the water. 

Slip a glass plate under the 
mouth of the bottle and remove 
it, reinverting at the same time. 
Now add to the water in the 
bottle a solution of blue Htmus 
and it will immediately turn red, 
showing the presence of an acid. 
In dissolving in the water, the 
nitrogen peroxide forms a mix- 
ture of nitric and nitrous acids. 
This is what happens in the 
making of nitric acid from the 
air. 

8. Preparation of Ammonia. — 
On a paper mix equal quantities 
of sal ammoniac and slaked 
lime. Fill a test tube one-half 
full of the mixture and fit it with 
a one-holed stopper and bent delivery tube as shown ui 
Fig. loi. Heat the test tube gently with a small flame and 
hold over the delivery tube a strip of moist red litmus 





Fig. 



loi . — Preparation 
ammonia. 



of 



346 The Boys' Own Book of Great Inventions 

paper. It turns blue as the anmionia gas is given off. 
This is a test for ammonia. 

Now invert over the delivery tube a dry test tube and 
continue to warm the mixture. After a few moments 
remove the tube full of ammonia gas and thrust it mouth 
down in a dish of water. The water will rise and fill the 
tube, showing the great solubility of ammonia. The gas is 
collected upward because it is lighter than air. 

The experiment showing the solution of the ammonia in 
the water may be varied by adding to the water in the 
dish a Httle blue litmus and coloring it red by the addition 
of one drop of acid. Now when the dry test tube of am- 
monia gas is inverted in the red Htmus the water will rise 
as before but will be immediately turned blue. 

9. Preparation of Hydrogen. — Hydrogen used for the 
inflation of balloons and Zeppelins and in the Haber proc- 
ess of making anxmonia may be made in the same appa- 
ratus as that used for nitric oxide. 

Instead of copper and nitric acid use zinc and dilute 
sulphuric acid. The acid may be prepared by pouring 15 
cubic centimeters of concentrated sulphuric acid into 90 
cubic centimeters of water. {Never pour water into the 
acid,) 

Cover the bottom of the bottle with granulated zinc and 
arrange the apparatus exactly the same as in the nitric 
oxide experiment, but do not place the delivery tube under 
the inverted bottle at first. Make all the joints perfectly 
tight and add the acid until the zinc is well covered. If the 
action does not start readily add a few drops of a solution 
of copper sulphate. Be sure that no flame is near the 
generator. 

When the action has been going briskly for about two 
minutes, place the delivery tube underneath an inverted 



Some Notable Achievements in Chemistry 347 

bottle of water and displace the water. Fill three bottles 
with the gas in this way. Stop the action by pouring water 
through the thistle tube. 

Remove one of the bottles and hold it mouth downward 
over the flame of a Bunsen burner. Note that the hydro- 
gen bums with an almost colorless flame. 

In the right hand hold a bottle of hydrogen mouth 
downward and beside it in the left hand an ''empty" bottle 
also mouth downward. Now pour the hydrogen upward 
into the "empty" bottle by quickly bringing beneath it 
the mouth of the bottle of hydrogen. After a moment 
bring both bottles mouth downward to the Bunsen flame. 
What property of hydrogen is shown by this experiment? 

Allow the third bottle of hydrogen to remain mouth 
upward for two minutes and then present to the flame. 
Where has the hydrogen gone? Why? 

10. Destructive Distillation of Coal. — In a hard glass test 
tube provided with a one-holed stopper and short straight 
glass tube place some powdered soft coal. Heat this 
strongly in the Bunsen flame and after a few moments 
ignite the gas. When no more gaseous matter can be 
driven off allow the test tube to cool. On the sides wiU be 
found some black, sticky stuff. This is the coal tar or that 
part that was not driven out and burned with the gas. 
Knock out the residue in the bottom and you will find a 
dry porous piece of coke. If you had placed a strip of 
moist red litmus paper in the gas before igniting it, you 
would probably have obtained the test for ammonia. 



Chapter XVIII 
THE STORY OF IRON AND STEEL 

Hand in hand with the rise and fall of nations has gone 
proficiency in the working of metallic ores and particularly 
in the metallurgy of iron and steel. At what time in the 
remote past primitive man through his knowledge of fire 
passed to a knowledge of metals and their wonderful prop- 
erties, so indispensable to his mastery of the earth, it is 
idle to conjecture. Certain it is that for long centuries 
before the Christian Era, metal working was a highly 
perfected art. Whether or not copper and tin were the 
first metals to be used and in their alloyed form of bronze 
characterized a long period of history in which the use of 
other metals was imknown, it is difficult to determine. 
Ancient ruins and the easy metallurgy of these ores would 
suggest this to be true. And yet iron has been found in 
the pyramids of Egypt built 4,000 years before Christ. 
Much evidence, too, points to a knowledge of iron by the 
Assyrians, Chaldeans and Babylonians, who occupied the 
plains of Mesopotamia at a much earlier period. But 
whatever the truth, the mastery of metals and their skillful 
adaptation to the varied arts of peace and war have spelled 
power and dominion— dominion at first over the material 
elements of nature, followed by the military and political 
sway of empire. 

Iron and steel have been the world's symbols of power 
from the days of Rome to the present moment. Ancient 
Spain before the rise of Rome was skilled in the working of 

348 



The Story of Iron and Steel 349 

iron. Hannibal's men equipped with Spanish swords 
made sad havoc in the Roman ranks at the battle of Can- 
nae, in 216 B. C. The famous blades of Damascus and 
Toledo even point to the tempering of steel as something 
of a lost art. When Caesar invaded England he found the 
Britons in the possession of iron. The Scandinavian Vikers 
used iron in their vessels even in Roman times. The vic- 
tory of William the Conqueror in 1066 must be attributed 
to warriors clothed in steel armor, having steel weapons in 
their hands and mounted on horses shod with iron. The 
rise of Great Britain to world-wide power has been coin- 
cident with the growth of her steel mills and the supremacy 
which she enjoyed in that industry until toward the close 
of the last century. With the increase in the output of her 
mines and the marvelous expansion of the Krupp steel 
works, Germany, before the war, was rapidly climbing to 
her "place in the sun." Indeed, it is her control of iron 
and steel, including the stolen mines of Belgiimi and north- 
ern France, that has made her the military octopus of the 
world. But across the ocean in America the steel industry 
has surpassed that of every other nation. Nowhere else in 
all the earth are there such inexhaustible stores of ore, 
coal and limestone. The stupendous output of her thou- 
sands of furnaces is being forged into steel without limit 
for armor plate, big guns, steel ships, aeroplanes, locomo- 
tives, shells, motor trucks and a score more of war-making 
essentials that in an avalanche of steel, steel and more 
steel will overwhelm the powers of darkness and inter- 
national brigandage. Steel is the fundamental essential of 
every war-making activity and that nation that controls 
it in largest measure can build the biggest merchant fleets, 
the most powerful guns, the largest battleships, the most 
aeroplanes and that almost infinite supply of ammunition 



350 The Boys' Own Book of Great Inventions 

indispensable to a military victory. Germany's output of 
steel, great as it is, is insufficient to forge the chains of 
world dominion. She has decreed for herself "world do- 
minion or downfall" and the answer of the mightiest steel- 
producing nation of the world is downfall. 

Primitive man ages ago probably stumbled on to the 
method of working ores. As he raked over the embers 
of some spent fire, he discovered globules of bright metal. 
It may have been tin or copper or perhaps iron. But 
whatever the metal, its lustre and properties of toughness, 
hardness and malleability must soon have demonstrated 
its superiority to wood and stone for hunting purposes 
and weapons of warfare. A repetition of this experience 
with the fire followed by examination of the rock upon 
which it was built gradually led to a knowledge of cer- 
tain ores and a deHberate attempt to duplicate the process. 

The Blast Furnace. — But a knowledge of the metallurgy 
of iron came very slowly. From Roman time to the discov- 
ery of America very Httle progress was made. The first 
"blast furnace " consisted of a hole in the ground into which 
alternately lumps of ore and charcoal were thrown, followed 
by blowing with a hand bellows. By vigorous work two men 
squatting over this crude furnace would produce a dozen 
pounds of the metal in a day. For comparison we may note 
that one of the big blast furnaces at any of our modern 
steel plants turns out 400 tons of pig iron every 24 hours. 
The famous Catalan forge representing the acme of the 
metallurgist's art all through the Middle Ages and until 
very recently still used in remote corners of the earth 
originated in Catalonia, Spain, nobody knows when. It 
closely resembles a blacksmith's forge, consisting simply 
of an open-top, brick-lined furnace fitted with a hand 
bellows. The heat obtained was not siifficient to melt 



The Story of Iron and Steel 351 

the iron but left it in a pasty condition suitable for hand 
forging. When the iron master learned the desirabiHty 
of using a flux to unite with the earthy impurities in the 
ore and by what tedious and baffling experiments he at 
last discovered • in limestone the ideal material for this 
purpose, no record discloses. 

Iron making as an industry, however, cannot be said 
to have established itself until the invention of the 
present type of blast furnace following the revival from 
the general lapse of knowledge experienced during the 
mediaeval period. The first furnace built on modern 
lines appeared in the lower Rhine Valley. It was only 
about sixteen feet in height and still unable to melt the 
iron. Improvements were made and the height increased 
imtil by 1340 the Belgian ''blow oven" yielded molten 
metal and the first cast iron in history was produced. The 
molten iron was drawn off in one large pool from which 
numerous smaller depressions led for the purpose of cool- 
ing. Because these depressions resembled a brood of 
young pigs the product of the blast furnace very early 
came to be called "pig iron." 

The fuel used in these early furnaces and for several 
centuries after was charcoal. Timber was abundant and 
charcoal was ideal both for fuel and the reduction of the 
ore. The destruction of the forests, however, particu- 
larly in England, produced a decline in the industry for a 
nimaber of years. Then about the middle of the eighteenth 
century Abram Darby of England discovered the process 
of coking bituminous coal. Coal was abundant in Eng- 
land and had been in common use for more than two 
hundred years. Furthermore, the coal and iron deposits 
were side by side, thus making ideal conditions for the 
•steel industry. There it was, too, in the small island king- 



352 The Boys^ Own Book of Great Inventions 

dom that this great basic industry had its first phenomenal 
development. 

In America forges and furnaces sprang up in every 
colony. The first iron smelted was in Massachusetts in 
1644. Centers of iron manufacture multipKed for two 
hundred years. The industry in those days was purely 
local, but the numerous forges scattered along the Atlantic 
seaboard and extending inland to the AUeghenies and the 
Ohio Valley did valiant service in the early pioneer days. 
They provided muskets, cannon and shot for our first 
two wars and the implements necessary to the subduing 
of a new country. The coming of the locomotive and the 
railroads in 183 1 gave a tremendous impetus to the in- 
dustry and started it toward that wonderful expansion 
that more than anything else has won for America the 
commercial supremacy of the world. 

The product of the old Catalan forge was wrought iron, 
or malleable iron. Prolonged heating with charcoal and 
later with the addition of a flux together with hammering 
and reheating produced a fairly pure quality of iron. It 
is commonly called soft iron and is the sort of iron a black- 
smith uses for forging and welding. At no point of the 
process had it been melted. The product of the blast fur- 
nace, however, is drawn off in a molten condition and is 
not nearly so pure. By melting and coming into intimate 
contact with the contents of the furnace the iron dissolves 
carbon, phosphorus, sulphur and silicon. The blast fur- 
nace process is much quicker, easier and cheaper, but the 
impurities make the iron useless for many purposes. It is 
brittle and cannot be forged either hot or cold. The im- 
purities, however, give it a lower melting point and where 
used without change it is remelted and cast. 

The Puddling Furnace. — Therefore, it became necessary 



The Story of Iron and Steel 353 

to purify blast furnace iron by reheating and hammering 
it in a forge. This was a very laborious process and did 
much to rob the blast furnace of any advantage it possessed 
over the older method. But in 1784 Henry Cort, an Eng- 
lishman, invented the ''puddling" furnace for changing 
the pig iron into wrought iron. It consisted of a basin- 
like hearth with a sloping, arched roof and a fire grate just 
beyond a low partition at one end. The pig iron is melted 
in this hearth and the flames and hot gases from the fire 
being deflected downward upon its surface burn out the 
carbon and other impurities. The hearth is usually first 
covered with a layer of iron oxide to assist in the oxida- 
tion. As the process continues and the iron becomes more 
nearly pure its melting point rises, making it assume a 
pasty condition. At this point a workman reaches into 
the furnace with a long rake and rakes or "rabbles " the 
pasty lumps over to quicken the process of oxidation. In 
this way a very pure product is obtained, but its pores are 
full of slag and to remove this Cort provided grooved rolls 
which repeatedly squeezed the hot iron and very quickly 
freed it from the slag. The puddHng furnace was a vast 
improvement and for producing wrought iron is still 
used. 

Another EngHshman, J. B. Neilson, in 1828 discovered 
that by preheating to about 600° Fahr. the blast of air for 
the blast furnace, its output could be doubled with no in- 
crease of fuel. Here was a very great cheapening in the 
cost of pig iron and coupled with the improved methods 
of converting it into wrought iron resulted in a much wider 
field of usefulness. 

Early Steel Making. — Steel was not much used in those 
days but for some purposes such as cutlery, the finest 
edged tools and rails for the locomotives, wrought iron 



354 The Boys^ Own Book of Great Inventions 

was too soft. Now the fundamental difference between 
wrought iron and steel is in the percentages of carbon that 
they contain. Wrought iron is nearly pure iron having 
not over .3 per cent of carbon, while steel has a carbon con- 
tent of from .5 to 1.5 per cent. Wrought iron is tough, 
pliable, inelastic and adapted to forging. To change it 
into hard elastic steel that can be tempered and made to 
take an edge it must be made to take on carbon. This was 
accomphshed by placing bars of the iron together with 
charcoal in a closed retort and heating them red hot. The 
heating was continued for several days and the iron grad- 
ually absorbed the carbon, being converted into a uni- 
form, high-grade steel, called blister steel. The process 
was slow and although the steel was of excellent quality, 
its cost for extensive use was prohibitive. As the needs 
for hard, tough, elastic iron multipKed, it became increas- 
ingly apparent that a quicker and cheaper process of pro- 
ducing steel must be developed. 

The Bessemer Process. — The solution of the problem 
was soon forthcoming. In 1856 Sir Henry Bessemer pre- 
sented to the British Association for the Advancement of 
Science his now famous process for quickly and cheaply 
converting pig iron into steel. It marked an epoch in 
world progress and ushered in the Age of Steel. Without 
it the marvelous material and commercial expansion of 
the last half century would have been impossible. Fleets, 
railroads, locomotives, skyscrapers, automobiles, big guns, 
machinery of all types and a thousand more necessities 
of modern industry never would have risen above the 
threshold of accompHshment. 

Sir Henry Bessemer was gifted with a genius for inven- 
tion. When only a lad of eighteen he devised an improved 
method for stamping deeds which was adopted by the 



The Story of Iron and Steel 355 

English Stamp Office without remuneration to the youth- 
ful inventor. Then in rapid succession he invented ma- 
chinery for making figured velvet, a type-casting machine 
and a process for the manufacture of bronze powder. In 
1854 he was working in France on an invention relating 
to projectiles. The necessities for this work brought for- 
cibly to his attention the inadequacy of existing methods 
for the manufacture of steel. The result was a series of ex- 
periments in an old factory at St. Pancras and the devel- 
opment of the Bessemer process. He conceived the idea 
of burning out the impurities from molten pig iron with 
a powerful blast of air. For this purpose he provided 
a huge egg-shaped crucible capable of holding 15 or 20 tons 
of the molten metal. It was lined with silica and mounted 
on trunions, one of which was hollow and led to a per- 
forated bottom for the passage of the blast of air. The 
crucible was rotated on its trunions to receive the charge 
and then tipped back in a vertical position for the air 
blast. As the oxygen of the air passed upward through 
the white-hot liquid iron, the impurities were quickly 
burned out, not over twenty minutes being required for 
almost as many tons of metal. The "blow" is accom- 
panied by a deafening roar and a sheet of flame, changing 
rapidly from red to white and then to a faint blue. When 
the color of the flame indicates that the carbon is gone, 
the blast is shut off and the requisite quantity of an iron 
alloy rich in carbon and manganese is added. After the 
blow the contents of the crucible are in composition es- 
sentially wrought iron, but to make steel carbon must be 
added. The purpose of the manganese is to deoxidize 
the iron which is left by the blow in a highly oxidized state. 
This process of incorporating the carbon and deoxidizing 
the iron requires but a few moments and the now molten 



356 The Boys' Own Book of Great Inventions 

steel is quickly poured or 'deemed" into ingot molds 
waiting below on a train of flat cars to receive it. 

Bessemer 's announcement was received by the iron 
makers of England with no little skepticism and ridicule. 
Its application in many places proved to be a disastrous 
failure. At that time Bessemer, himself, had not per- 
fected the process in all its details as described above and 
as we know it to-day. With undaunted perseverance, 
however, he went to work and by 1859 all difficulties had 
been overcome. The vitally important matter of adding 
the carbon-manganese alloy was due to Robert Mushet. 
But previous experiences had brought such ill-repute to 
the process that no one would have anything more to, do 
with it. Therefore, Bessemer, v/ith the financial assist- 
ance of friends built his own works at Sheffield and entered 
into open competition with his critics. The results very 
shortly demonstrated the superiority of his process, and 
the production of high-grade Bessemer steel at about $100 
a ton cheaper than the prevailing market price forced 
a speedy surrender of the "enemy." Bessemer licensed 
the use of his patents both at home and abroad and ten 
years after the first announcement, his revenue therefrom 
was a half million annually. Both from this source and 
his great works at Sheffield, he amassed a large fortune. 
In fourteen years his steel plant had yielded 81 times its 
original cost. In later years he devoted himself to an un- 
successful invention for preventing the rolling of a ship 
at sea and to the improvement of telescopes. His country 
knighted him, he was honored with a fellowship in the 
Royal Society and the world will never cease to be grate- 
ful to the inventor who made possible cheap and abun- 
dant steel. 

The inability to handle ore containing more than very 



The Story of Iron and Steel 357 

small amounts of phosphorus and sulphur in the Bessemer 
converter was one of the early difficulties experienced 
with the process. Phosphorus made the steel brittle when 
cold and sulphur made it brittle when hot. Consequently 
only certain ores could be worked by the Bessemer method 
and many very rich deposits were unavailable because of 
their phosphorus content. Then in 1878 Messrs. Thomas 
and Gilchrist devised the ''basic Bessemer process." In- 
stead of lining the converter with sand, an acid substance, 
as had been done before, they substituted a dolomite lining 
which is basic in character, or the opposite of acid. Phos- 
phorus, which is, itself, acid in character unites with the 
basic lining and is thus eliminated. In addition, to assist 
in the removal of the phosphorus, Hme, another basic sub- 
stance, is put in with the charge of molten pig iron. 

Open Hearth Process. — The Bessemer process had the 
two great advantages of being quick and cheap, but it 
lacked control. So quickly is the pig iron converted into 
steel that there is no opportunity to test the product and 
govern in any scientific way its quality. The whole suc- 
cess of the process depends on keeping the iron in a molten 
condition and with no other source of heat than that from 
the burning impurities, the iron would soon ''freeze" if 
all haste were not made. 

But in 1856, the same year that Bessemer took out his 
patents, William Siemens invented another process for 
steel making very similar to the puddling furnace for 
wrought iron. About eight years later a Frenchman named 
Martin improved it by adding a regenerating system for 
conserving the waste heat and made the process a commer- 
cial success. 

In the open hearth furnace on each side of an immense 
hearth are two large chambers loosely fitted with a fire- 



358 



The Boys^ Own Book of Great Inventions 



brick checkerwork. The hearth is covered with an acid 
or basic Hning according to the kind of ore to be worked 
and this is followed with a charge of pig iron, scrap steel 
and iron oxide. Connected with the brick checkerworks 




OPCN MEIARTH TURN AC El 
Fig. I02. 

are supplies of air and gas. The gas is generated in a gas 
producer by blowing air in the proper proportion through a 
hot bed of coal. Through one checkerwork on one side 
gas is blown and through the other air, the gas and air 
meeting over the hearth and burning with a fierce heat. 



The Story of Iron and Steel 359 

At the same time the hot combustion gases sweep out 
through the checkerworks on the other side, raising them 
to a white heat. After about 20 minutes the gases are 
shifted, the air and producer gas entering through the 
hot checkerworks and the combustion gases passing out 
through the opposite ones. In this way energy is saved 
and the pre-heating of the gas and air increases enormously 
the temperature of the furnace. As a result the pig iron 
and scrap steel melt and the flames and iron oxide burn 
the impurities out of the iron. The time required for a 
charge is about 8 or 10 hours, but the process is under per- 
fect control. Samples are removed and tested. If too 
acid, lime is added; if too basic, silica; if the carbon con- 
tent is too high more scrap steel is added and at the end 
just the requisite quantity of ferro manganese to give the 
grade of steel desired. 

Open hearth steel costs more to make but it is more uni- 
form, more dependable and of greater strength than that 
made by the Bessemer process. So great is the demand 
for open hearth steel in this country that the Bessemer 
converters are being rapidly displaced. They afforded 
an excellent bridge over which to pass from the age of iron 
to the age of steel, but having done their full part of the 
world's work, like the stage coach and sailing vessel, they 
must give place to something better. 

The Supremacy of the United States. — In 1880 the steel 
industry in England had reached its zenith, but from that 
date the ascendency of America has been rapid and certain. 
To-day the United States produces more than half of the 
total steel output of the world. Favored with the richest 
and most abundant deposits of ore, coal and flux to be 
found anywhere in the earth and having a tariff -protected 
home market coupled with a land of boundless and unde- 



360 The Boys' Own Book of Great Inventions 

veloped resources, the growth of the industry in this coun- 
try has become one of the marvels of the nineteenth and 
twentieth century progress. The scarcity of labor incident 
to the rapid growth of a new country has forced the indus- 
try upon a machine basis. Electric and steam shovels, 
cranes, rollers, shears, stamping machines and furnace 
charging apparatus besides a host of other labor-saving 
devices have eliminated the human factor to a very large 
extent. In this respect the industry here differs from that 
of any other country. 

The better ores having been exhausted in the East, 
about 1880 the ore supply began to shift to the Lake Su- 
perior region where He the richest and largest deposits of 
the earth. But the deposits of coal and the furnaces were 
in the East and therefore the ore must be transported a 
thousand miles to the iron centers about Pittsburg and the 
lake ports. The problem was stupendous, but the Great 
Lakes afforded a natural highway and it was soon solved. 
The whole of this thousand-mile route fairly bristles with 
machinery at every point from mine to furnace. The ore 
lies on the surface or very close to it and is loaded directly 
into the long ore trains with a myriad of steam shovels. 
The ore trains run to Duluth, about 80 miles distant, and 
automatically dump their loads directly into huge pockets 
on the docks. Large ore freighters, Kttle more than hollow 
shells but with an enormous capacity, lie alongside the 
docks and through spouts and hatches placed at intervals 
of 12 feet are filled at the rate of from 80 to 300 tons per 
minute. A ship holding close to 10,000 tons has been 
loaded in 25 minutes. One of these ungainly "whale backs " 
has scarcely had time to tie up before it is ready to start on 
its return trip toward the seething furnaces of the East. 

The unloading machinery at the lake ports works on an 



The Story of Iron mid Steel 36 1 

equally large scale. In the old days these immense cargoes 
were unloaded with shovels, buckets, windlasses and wheel- 
barrows. But all this has changed. Huge clam-shell 
unloaders dip into the hold of the ship and when their 
gigantic jaws come together they scoop up 17 tons of ore 
at a time and quickly Uft it into the bin above. From the 
bin it is run into waiting ore cars below to be carried to the 
furnaces or it is deposited in the buckets of a great canti- 
lever bridge to be transferred to the reserve stock pile. 
In 3 hours this electrically operated machinery will unload 
10,000 tons of ore and before the war it was done at a cost 
of 2 cents per ton. 

At the steel plant this ore, which at no point of its thou- 
sand mile journey has been lifted by human muscle, is 
hoisted 90 feet to the top of a huge blast furnace that 
swallows every day 800 tons of ore, 400 tons of coke and 
100 tons of limestone, yielding an output of 400 tons of pig 
iron. From the blast furnace the iron, still in the molten 
condition, is run into huge ladles and carried directly to 
the converters or open hearth furnaces where very shortly 
it becomes steel and in the shape of 7,000-pound ingots is 
deposited in soaking pits preparatory to its trip through 
the rolls to be shaped into steel rails, rods, girders or what 
not. Machine handled at every point, it may be truly 
said that ''steel is not made with hands." 

Some faint idea of the magnitude of the steel industry 
in the United States may be obtained from the fact that in 
19 1 7 approximately 80,000,000 tons of ore were mined, 
yielding half that number of tons of pig iron and represent- 
ing in the unconverted state a value of close to three- 
quarters of a billion dollars. This vast amount of ore 
would make a train of ore cars carrying 50 tons to the car 
and stretching a distance of 6,060 nailes or nearly a quarter 



362 The Boys' Own Book of Great Inventions 

of the circumference of the globe. During this same year 
the United States Steel Corporation employed a force of 
more than a quarter of a milKon and paid out in salaries 
and wages $347,370,400. 

In the Great War steel is paramount. At the memorable 
battle of Verdun to make good the invincible determina- 
tion of the men who said, ''They shall not pass," required 
an expenditure of 60,000,000 shells containing 1,800,000 
tons of steel. In the first 78 minutes of the big offensive on 
the Western Front during the spring of 19 18, Germany 
used 650,000 shells, or as many as were employed in the 
entire Franco-Prussian War of 187 1. To maintain one 
man in France requires 2 tons of shipping or 2,600,000 tons 
for the first army and this all represents steel construction. 
Besides, steel ships must make good the Allied loss in the 
first four years of war of 11,827,572 tons. To build one 
8,000- ton ship requires 3,200 tons of steel. In addition 
millions of tons of naval construction are under way. A 
railroad program vital to the movement of men, fuel and 
munitions calls for 100,000 cars and 1,025 locomotives. 
This item alone will require 1,200,000 tons of steel costing 
$324,000,000. There is an immediate further need for 
between 2,000,000 and 3,000,000 steel rails and the mills 
working 24 hours a day are two years behind their orders. 
Then, too, there must be steel for motor trucks, tractors, 
farm machinery, gasoline engines, guns of all descriptions, 
ammunition in prodigious and inexhaustible quantities 
and for engineering construction. And as though these 
stupendous demands were not enough, every day orders for 
thousands more tons of steel pour in from our Allies across 
the sea. Upon the steel industry of America rests in largest 
measure the success of the war and the hope of democracy. 

Alloys. — Strange as it may seem the presence in steel of 



The Story of Iron and Steel 363 

small quantities of other metals changes to a very remark- 
able degree the qualities of the steel. Such mixtures of 
two or more metals melted together are called alloys. 
Among the common alloys, other than those of steel, are 
bronze, brass, solder. Babbit metal, lead shot and German 
silver. All of these alloys have particular properties not 
possessed by the constituent metals alone, which increase 
very markedly their range of usefulness. Differences in 
hardness, melting points, tensile strength, ductihty, tough- 
ness and electrical resistance are the more common. Some 
of the effects of other metals on steel are given in the fol- 
lowing paragraphs. 

Manganese. — In the making of steel it will be remem- 
bered that manganese is necessary as a deoxidizer. Steel 
having from 2^ per cent to 7 per cent of manganese is 
very brittle, but with more than 7 per cent and up to 18 per 
cent practically a new metal results possessing great 
strength, elasticity and hardness. It is used for the jaws 
of rock crushers, safes, jail bars, etc. 

Nickel. — This was one of the first metals to be used in 
steel and is one of the most valuable in its effects. It 
increases the tensile strength, ductility and elastic limit. 
Nickel steel is used for automobile construction and for 
the moving parts of all kinds of machinery. When con- 
taining 30 per cent of nickel the steel can be drawn into 
wire and this large percentage makes it non-corrosive and 
therefore well adapted for ships' hawsers, marine . cables 
and other steel construction which is exposed to the action 
of salt water. 

Steel containing 36 per cent of nickel gives an alloy 
having the lowest known coefficient of expansion, that is, 
it changes its volume with change of temperature the least 
of any known metal or alloy. It is used in clock pendu- 



364 The Boys' Own Book of Great Inventions 

lums. If 42 per cent of nickel are present the alloy has the 
same rate of expansion as glass and is, therefore, useful in 
sealing the filaments into incandescent lamp bulbs. 

Chromium. — Chrome steel is intensely hard. In 1882 
chrome steel shells were made that penetrated wrought 
iron plates 8 inches thick. It is generally used in conjimc- 
tion with nickel, the chromium giving hardness and the 
nickel elasticity. Such steel has extensive uses in the 
manufacture of guns, armor plate and projectiles. 

Vanadium. — This is a rare earth metal which has the 
most powerful effect upon steel for the quantity used of 
any element. So rare was the metal at first that a pound 
of it cost $10,000, but there has since been found a large 
deposit in South America. As Httle as 2 per cent raises the 
tensile strength and elastic lunit of mild steel by 50 per 
cent. It is used for the highest classes of tool steel. In 
high speed steels it trebles and quadruples their cutting 
qualities. The heat developed does not draw the temper. 
It also produces what is called *^ anti-fatigue" steel. Steel 
which is alternately under tension and compression tends 
to become brittle or ^'fatigued," but vanadium resists this 
tendency. It gives increased strength with diminished 
weight and is, therefore, used in automobiles, engines, 
aeroplanes, tractors, etc. 

Tungsten. — ^This metal prevents the softening effect on 
steel at high temperatures and increases the hardness of 
steel. Steel having 6 per cent of chromium and 10 per 
cent of tungsten makes excellent high-speed steel for lathe 
tools. Tungsten increases the magnetic retentive power 
of steel and is used in making permanent steel magnets 
for use in electrical measuring instruments where the 
strength of field must be uniform from year to year. 

Molyndenum has effects similar to that of tungsten. 



The Story of Iron and Steel 365 

SIMPLE ALLOYS TO MAKE 

Brass.:— If you have made the resistance furnace de- 
scribed in the experiments under high temperatures and 
have available electric current of no volts pressure you 
will have no trouble in making brass. To melt the copper 
a temperature of 1084° C. will be required, but this furnace 
will give it. 

Place in a fire-clay crucible of suitable size to fit the 
furnace 70 grams of copper and have at hand 30 grams of 
zinc. When the copper has melted add the zinc, which 
will quickly dissolve and mix with the copper. 

When the zinc and copper have mixed seize the crucible 
with tongs and plunge it into a pail of cold water. The 
brass will very quickly soHdify and may be knocked from 
the crucible. 

Bronze. — ^This may be made in the same way using 75 
grams of copper, 15 grams of zinc and 10 grams of tin. 
Do not add the zinc and tin until the copper is melted. 

Solder. — Solder may be easily made in a clay crucible 
over an ordinary Bunsen burner. Use equal parts by 
weight of lead and tin. 

To run this into sticks make a Plaster of Paris mold. 
Mix the Plaster of Paris in a pasteboard box-cover and 
while still soft press into it two or three lead pencils. Into 
these depressions the molten metal can be poured. 

Wood's Metal. — ^This is an alloy that melts in hot water 
of about 70° C. Therefore it may be made over a Bunsen 
burner. Use 15 grains of cadmiiun, 20 grams of tin, 40 
grains of lead and 80 grams of bismuth. 

This alloy may be molded as before. On placing a stick 
of it in hot water it will melt and run about the bottom of 
the beaker Uke mercury. 



366 



The Boys' Own Booh of Great Inventions 



Type Metal. — This is an alloy having the property of 
expanding on cooling instead of contracting. Therefore 
in casting type the cooling metal expands, filling the edges 
out and giving clear-cut definite type. 

Melt over a Bunsen burner 75 grams of lead, 20 grams 
of antimony and 5 grams of tin. 



Chapter XIX 

GALILEO AND THE TELESCOPE 

Thus far we have dealt only with some few of the great 
inventions which have marked epochs in the material 
progress of the race. So absorbed we may have become in 
contemplating these achievements that it is possible our 
minds have grown to a certain degree earth-bound. In the 
midst of the daily hubbub that surrounds us, we are apt 
to forget that this planet and all it contains is but a tiny 
atom of the universe. Keenly interested in the immediate 
needs of our material existence, engrossed in a world war 
of unparalleled magnitude, and deeply conscious of the 
power for weal or woe of the tremendous forces of nature, 
we give little thought to the heavens above and the infinite 
depths of space. But did you ever consider that time and 
space are without beginning and without end? Can you 
think of a time when there was no time or imagine a realm 
where there is no space? If you should take the wings of 
the morning and fly to the '' uttermost parts of the earth," 
would there not still be space? And did you not ever 
reflect that every star in the heavens is doubtless the center 
of a solar system, with worlds like our own? Have we any 
good reason for doubting that these worlds are peopled 
with beings engaged in affairs as momentous as our own? 
This little planet teems with life from the myriad of micro- 
scopic organisms in a drop of stagnant water to the mam- 
moth animals of early geologic time. Life is the order of 
the universe and ours can be but an infinitesinal portion 

367 



368 The Boys^ Own Book of Great Inventions 

of it. Only when we thus try to grasp something of the 
immensity of it all, can we have even an approximate 
appreciation of the relatively insignificant part which our 
planet plays in the universe of time and events. Therefore, 
we may truly say that the genius who perfected an instru- 
ment enabling men to push heavenward by millions of 
miles the frontiers of the known universe and to add to it 
worlds without end, is the greatest inventor of the ages. 
Such a genius and such an invention the world has in 
Galileo and the telescope. Musician, scholar, teacher, 
physicist, inventor and astronomer, Galileo stands forth 
to-day, after a lapse of three centuries, as one of the giant 
intellectual leaders of all time. Breaking away from the 
traditional bondage of mediaeval Europe to Aristotle and 
the past, GaHleo dared to think for himself and blazed the 
way to the independent thought and freedom of modem 
science. 

Although the first telescope was doubtless made in 
Holland in 1608, and came about from the accidental plac- 
ing of one lens over another, Galileo reinvented it at prac- 
tically the same time and was the first to apply it to an 
exploration of the mysteries of the stars and planets. His 
first simple telescope consisted of a lead tube with a double 
concave eyeglass and a double-convex objectglass. It 
made objects appear three times nearer and nine times 
larger. He very quickly made several others, each being 
of greater power than the preceding, and in a short time 
had a telescope that brought objects thirty times as close 
and magnified them nearly a thousand times. With this 
instrument he made his epoch-making discoveries in as- 
tronomy. To his amazement he found that he could count 
ten times as many stars in the sky as his unaided eye was 
able to detect. Contrary to the common belief, then, the 



LfcMr33 



Galileo and the Telescope 369 

stars were not all equidistant from the earth. Those that 
were brought into view with his telescope must be at 
greater distances than those revealed with the naked eye. 
With the first sweep of his telescope across the heavens, he 
extended the bounds of the universe by miUions of miles, 
and at a single glance destroyed a traditional error of all 
previous time. Certainly no other observation, even with 
the most powerful of modem telescopes, ever disclosed as 
much. It was the beginning of a new knowledge, which 
was destined to break the fetters of intellectual bondage 
and enlarge men's minds to a truer conception of the uni- 
verse of which they are a part. 

This astronomer of Padua and Florence next turned his 
magic tube on the beautiful Milky Way. He showed this 
belt of silvery Hght to be made up of myriads of faint stars, 
too small to be distinguished without optical aid; and at 
such measureless distances away that they Hterally seem 
to rub elbows with each other. Yet this galaxy of stars 
represents innumerable blazing suns like our own, sepa- 
rated from each other by millions and miUions of miles. 
In these first few days with the telescope, knowledge grew 
more rapidly than at any time before or since. 

A still greater discovery was that of the four moons of 
Jupiter. Here was a miniature sun with a system of re- 
volving planets. With his telescope, Galileo was able to 
observe their motion about the great planet. Surely the 
doctrine of Copernicus as to the central position of the 
sim and its revolving planets, including the earth, was 
true. The ancient system of Ptolemy, making the earth 
the center of the universe, disappeared before the revela- 
tions of the telescope. The fame of GaHleo and his dis- 
coveries spread abroad and great personages crowded to 
Padua to view the heavens for themselves. 



370 The Boys^ Own Book of Great Inventions 

Galileo also discovered that the planet Venus passes 
through phases just as our moon does. He mistook the 
rings of Saturn for two small sister planets, but corrected 
the error later. He studied the surface of the moon and 
described its lofty mountains and deep volcanic craters. 
Sun spots were also observed and by noting the interval 
between the disappearance of a particular sun spot and 
its reappearance, Galileo was able to prove the rotation of 
the sun on its axis. 

But so intrenched were superstition and error in those 
dark days of the Inquisition, that instead of being recog- 
nized as the greatest scientist and discoverer of his time, 
GaHleo was persecuted by the Roman Church and com- 
pelled to recant his belief in the Copernican doctrine. His 
famous book defending the theory that the earth turns on 
its axis and not the sun about the earth, was confiscated. 
The announcement of his recantation was promulgated 
throughout Europe and his humiliation made as complete 
as possible. Yet the punishment meted out for those days 
was exceedingly mild, and he was soon permitted to return 
to his home. There, amid failing eyesight and eventual 
bhndness, Galileo did much important work in several 
fields of physical science and, in 1642, died at the age of 
seventy-eight. 

Although his brilliant discoveries in astronomy eclipse 
everything else he did, his contributions to Physics are the 
foundation stones of this important science. Every school- 
boy knows how, at the leaniQg tower of Pisa, he disposed 
of Aristotle's myth about the times of falling bodies, prov- 
ing that bodies of different weights fall in the same time. 
Later, iu a series of classic experiments, he worked out the 
exact laws of falling bodies for all subsequent time. He 
studied the pendulum and discovered one of its funda- 



Galileo and the Telescope 371 

mental laws. He made the first thermometer. By means 
of signals flashed from two distant hills in Tuscany, he 
attempted to measure the velocity of light. He made 
experiments with floating bodies, and invented a pump 
for raising water. He was the first investigator who 
had the sense and courage to go directly to nature for the 
answers to his questions, instead of consulting what Aris- 
totle had said two thousand years before. Therefore, he 
must be counted the world's first great scientist. 

Since the days of Galileo a host of briUiant scientists and 
mathematicians have carried forward his work. There 
was Kepler, contemporary of GaHleo, who discovered the 
laws governing the motions of the planets. Sir Isaac 
Newton, born the year following GaHleo's death, demon- 
strated the composite character of hght, constructed the 
first reflecting telescope, discovered the universal law of 
gravitation, explained the tides, and occupies a place 
second only to the great astronomer of Tuscany. Friend 
and associate of Newton was Edmund Halley, a very 
great astronomer, and forever famous because of the dis- 
covery of the comet bearing his name. Then there were 
the Herschels, the elder of whom gave the world the bril- 
Hant and imaginative conceptions of the constitution and 
physical nature of the heavenly bodies. His monster 
telescopes, built with his own hands, were the first to 
approach the excellence of modern construction. Laplace, 
the masterful French mathematician, carried forward the 
work of Newton, concerning the movements of the heav- 
enly bodies, and has immortalized his name in his wonder- 
ful conception of the Nebular Hypothesis. The Earl of 
Rosse devoted his Ufe to the construction of great tele- 
scopes. Flams teed and Sir George Airy have left an en- 
during monument in the famous observatory that crowns 



372 The Boys^ Own Book of Great Inventions 

the summit of Greenwich Hill. Le Verrier and John C. 
Adams, working independently of each other, gave the 
world conclusive proof of the universal law of gravitation 
in their discovery of the planet Neptune. Kirchoff estab- 
lished the principles of spectrum analysis and made pos- 
sible a knowledge of the elements in the most distant stars. 
Fraunhofer mapped the dark lines in the sun's spectrum 
and explained their significance. In this country. Young, 
Pickering, Newcomb and Lowell, among a host of others, 
have done important work. These are but a few of the 
great limiinaries of the celestial world and include none of 
its satellites. In unselfish devotion to the pursuit of truth 
and knowledge, and in a spirit far removed from the sordid 
commercialism of this world, these men have given their 
Hves to the noblest of all sciences, astronomy. 

Telescopes are divided into two classes, refracting and 
reflecting. In the former, images are produced through the 
power of lenses to refract or bend the rays of Kght. In the 
latter, the rays from a distant object are reflected by con- 
cave mirrors so as to produce magnified images which are 
viewed through an eyepiece containing lenses. GaKleo's 
telescope was of the refracting type. The essential features 
of such a telescope are an objective for producing an image 
of the object and an eyepiece with which to observe it, 
either of which may consist of one or more lenses. The 
objective gives a real image, that is, one that could be 
focused on a screen, while the eyepiece gives a virtual 
image similar to what is seen when you look through a hand 
magnifier. A real image is always inverted and a virtual 
image is upright. It should be noted that even the most 
powerful telescopes are unable to magnify the stars, so 
vast are their distances from us. 

Many difficulties were encountered in making the first 




By courtesy of John A. Brashear. 
The world's largest reflecting telescope at the Dominion Astronomical Observatory, 
. ' ^ . \ ' Victoria, Canada. 



Galileo and the Telescope 373 

telescopes. A convex lens of short focal length always 
produces a color fringe owing to the dispersion of light near 
the edges. This was very troublesome and at first could 
be overcome only by grinding lenses almost flat and there- 
fore of great focal length. This necessitated very long and 
unwieldly telescopes awkward to manipulate and requiring 
a prodigious amount of time and patience in their use. 
Achromatic lenses were later devised to overcome this 
difficulty, but before this time, Newton, despairing of 
success with the refracting type, built the first great re- 
flector. 

The largest refracting telescope in the world is the 40- 
inch telescope at the Yerkes Observatoiy of the University 
of Chicago, Williams Bay, Wisconsin. The 36-inch re- 
fractor at the Lick Observatory, Mount Hamilton, Cali- 
fornia, comes second. These and a number of other famous 
refractors were designed and constructed by the American 
firm of Warner and Swasey, at Cleveland, Ohio. This 
firm has also recently constructed the world's largest 
reflecting telescope for the Dominion Astronomical Observ- 
atory, Victoria, Canada. The reflecting mirror for this 
monster telescope is 72 inches in diameter and weighs 2% 
tons. It was made by John A. Brashear, of Pittsburgh, 
Pennsylvania, one of the world's greatest opticians. The 
telescope as a whole weighs 55 tons and rests upon massive 
piers of reinforced concrete. Another American firm that 
has done conspicuous work in the difficult art of making 
refracting telescopes is that of Alvan Clark and Sons. 
Nearly all of the great refractors have been made in 
America. 

Nothing has contributed so much to the broadening of 
men's minds as the revelations of the telescope. It has 
done more than any other invention to destroy ignorance 



374 The Boys^ Own Book of Great Inventions 

and superstition and to enable men to understand and 
interpret the great laws of the universe. And since we 
find the universe and its laws intelligible, must it not follow 
that back of them are thought and purpose and intelli- 
gence? No inteUigible creation ever proceeded from a 
nonintelligent source. Every invention described in these 
pages is the product of thought. By means of suitable 
mechanisms the purpose in the mind of the inventor is 
materialized. If there is no purpose, there can be no in- 
vention. Every material creation must first exist as a 
mental creation; and what a machine is to an inventor, so 
is the universe to the Creator. If this universe did not 
represent thought and purpose, then Nature would be an 
insoluble riddle. Its forces would be meaningless and 
inexpHcable. It would not be amenable to himian intelH- 
gence and there would be no medium of mutual commu- 
nication. The very fact that we can understand nature 
and her laws compels us to affirm personality back of them. 
From this conclusion we cannot escape. No one can look 
into the measureless distances of space and contemplate 
the infinite universe of perfect law, without irresistibly 
feeling that back of it all stands the Supreme Inventor of 
the Ages. 

EXPERIMENTS WITH MIRRORS AND LENSES 

I. Concave Mirror.— Plsice a concave mirror of about 
2}4 inches diameter and 6 inches focus on a table and 
resting against a vertical support. Place a lighted candle 
at more than twice the focal length from the mirror and a 
Httle to one side of a perpendicular line to its center. Move 
a white cardboard screen back and forth in front of the 
mirror, and at a distance of more than once and less than 



Galileo and the Telescope 



375 



COMPOUND 
MICROSCOPE 



twice the focal length an inverted real image, smaller than 
the object, will be obtained. 

Standing back some distance from the mirror, place the 
eye in line with the image and an inverted candle will seem 
to be suspended in space at the position where the screen 
was held. 

Repeat the above experiments, moving the candle nearer 
to the mirror. You wall find a point — twice the focal 
length — where object and im- 
age will be equidistant from 
the mirror and of the same size. 
When the candle is placed 
within this distance, the image 
moves farther away and be- 
comes magnified. 

2. Virtual Image with Con- 
vex Lens. — Using a double 
convex lens of 4 inches focus, 
place it at a distance of less 
than the focal length from 
your hand and look through it. 
A magnified image appears. 
This is a virtual image and 
the sort of an image obtained 
with the eyepiece of a tele- 
scope or compound micro- 
scope. 

3. Real Image with a Convex Lens. — Bend wire so as to 
form a lens holder and mount a double convex lens of about 
12 or 14 inches focus on a yardstick. Hold the lens and 
stick so as to get the view from an open window and behind 
the lens move back and forth a white cardboard screen. 
A distinct inverted image of some distant object will be 



(i= 



C:= 




Fig. 103. 



376 The Boys^ Own Book of Great Inventions 

obtained. This is a real image obtained by placing the 
screen at the position where the rays of light from the 
object are brought to focus by the lens. 

4. Real Images of a Candle. — Perform the same experi- 
ments with the lens as you did with the concave mirror, 
and very similar results will be obtained. In this case, 
however, object and image will be on opposite sides of the 
lens. 

5. A Compound Microscope. — Clamp two lenses of about 
2 or 3 inches focal length to an upright support, as shown 
in Fig. 103. Place a piece of white paper with a short arrow 
marked on it for object below the objective. Mount the 



A&TROfNOMICAL 
TEILEISCOPE 




Fig. 104. 

objective so that it will be more than once but less than 
twice the focal length from the object. Now move the eye- 
piece up and down until a distinct magnified image appears. 
The centers of both lenses must be in the same straight 
line. 

6. The Astronomical Telescope. — For objective, mount 
on a yardstick a double convex lens of about 14 inches 
focal length and an eyepiece of not over 4 inches. Place 
the centers of the two lenses exactly on a line and at a 
distance apart equal to the sum of their focal lengthsc 



Galileo and the Telescope 377 

With a little adjustment of the eyepiece a distinct, in- 
verted and magnified image of distant objects will be 
obtained. 

If desired, these lenses may be fitted into the ends of 
paper tubes blackened on the inside and telescoping into 
each other. 

A telescope of sufficient power for simple observations 
of the moon and several of the planets may be made by 
mounting in similar manner round spectacle lenses, num- 
bers 5 and 30, Number 5 will be the eyepiece and number 
30 the objective. 

The focal length of a lens may be determined by measur- 
ing the distance between the lens and the position of the 
image of some distant object. 

Apparatus and material for performing any of the exper- 
iments described in this book may be obtained from The 
Standard Scientific Company, 70 Fifth Avenue, New 
York City. 



INDEX 



Acetylene lamp, 307 

light, 30s 

welding, 315 
Acheson, Dr. Edward G., 312 
Adams, John C, 372 
Aerials, 103, 120 
Aeroplane, 142 

and the future, 154 

bombing, 153 

explanation of, 160 

Handley-Page, 153 

models, 168-172 

principles of, 156 

scouting, 152 

speed of, 166 

stability, 162 

steering, 162 

tractor, 153 

Wright, 146, 147 
Agamemnon, 37 
Agriculture, 232 

experiments, on, 240 

progress of, 236-239 
Alundum, 314 
Alloys, 362 

preparation of, 365 
Ampere, Andre Marie, 265 
Arago, 26 

Argonaut Junior, 176 
Assassin of the sea, 1 73 
Atmosphere, buoyancy of, 136, 167 

pressure of, 136, 167 



Audion Amplifier, 58 
Automobile, 226 
Aviation, military, 151 
story of, 134 

Balloon, altitudes attained, 142 

dirigible, 138 

first, 137 

in wartime, 137 
Ballonnet, 138, 139 
Barton, Enos M., 55 
Baxter, William, 29 
Bell, Alexander Graham, 40-52 

and wireless, 74 

opening transcontinental service, 

57 
Bell Telephone Association, 50 
Benzol, 338, 339, 340 
Bessemer process, 354 

Sir Henry, 354 
Birkeland, 329 
Blake, Dr. C. J., 44 
Blake, Clarence, 51 
Blast furnace, 350 
Bleriot, Louis, 149 
Branley, Professor E., 80 
Bradley, 329 
Brashear, John A., 373 
Brennan, Louis, 10, 11 
Bright, Charies T., 36 
Bushnell, David, 173 
Buzzer, a simple, 271 



379 



38o 



Index 



Cable, Atlantic, 35 

final triumph of, 38 
Capacity, electrical, 98, 105, 107 
Carborundum, 312 
Carburetor, 220 
Cartesian diver, 190 
Carty, Col. J. J., 54, 56, 130 
Catalan forge, 350 
Cavallo, Tiberius, 136 
Cavendish, 136 
Cayley, Sir George, 143, 213 
Cells, electric, 252-256 
Chanute, O., 144 
Charles and first balloon, 137 
Chemical effects of the electric 

current, 261 
Chemistry, achievements in, 326 

experiments, 341 
Chicago, Milwaukee and St. Paul 

R. R., 296 
Chili saltpeter, 327 
Clark, Alvan, 373 
Clerk-Maxwell, 76, 77 
Clermont, 204 
Coal tar, 335 
Coherer, 80, 82 
Coil tuning, 122 
Coke ovens, by-product, 338 
Communication, early means of, 25 
Compound steam engine, 201 
Condenser, 96, 120, 122 

grouping of, loi 
Conning tower, 182 
Copernicus, 369 
Copper plating, 262 
Cordite, 334 
Cornell, Ezra, 30 
Cort, Henry, 353 
Coupling of circuits, 108 

dose, 109 



Coopling of circuits, loose, 109 
Crane, Dr. Frank, 227 
Crookes, Sir William, 328 
Curtiss, Glenn G., 150 

Davy, Sir Humphrey, 277, 256 
Decoherer, 83 

De Forest, Dr. Lee, 57, 89, 127 
Destructive distillation, 336 
Detector, wireless, 106, 112, 121 
Diamonds, artificial, 311 
Diesel oil engine, 183 
Dolbear, Prof. A. E., and the tel- 
ephone, 50, 52 
and wireless, 75 
Duddell, 124, 125 
Duncan, Robert K., 340 
Dyestuffs, 336 
Dynamite, 333 
Dynamo, 284 

Edison, Thomas A., and duplex 
telegraphy, 35 
and the electric lamp, 301 
and the electric motor, 287 
and the telephone transmitter, 

51 

and wireless, 75 
Effects of the electric current, 256 
Electro-magnet, 26, 266, 269 
Electro-magnetic waves, 78, 82, 92, 

93, 100 
Electricity, 244 
Electrolysis of water, 261 
Electrotyping, 264 
Electro-magnetism, 265 
Electric welding, 314 
Ericsson, John, 213 
Essex Institute, 49 
Ether of space, 92, 124 



Index 



381 



Experiments on aeronautics, 167 
on agriculture, 240 
on chemistry, 341 
on effects of, the electric current, 

258 
on electro-magnetism, 267 
on submarines, 190 
on the gyroscope, 21 
with alloys, 265 
with electric lighting, 306 
with high temperatures, 321 
with induced currents, 280 
with mirrors and lenses, 375 
with static electricity, 246 
with steam, 210 
with the electric motor, 289 
with wireless, 115 

Explosives, 327 

Eyde, 329 

Faraday, Michael, 274 
Farman, Henry, 148 
Fessenden, Professor, 89 
Field, Cyrus W., 35 
Fire and high temperatures, 309 
Ford Power Plant, 292 
Foucault, Leon, 9 
Franklin, Benjamin, 245 
Fraunhofer, 372 

Fulton, Robert, and the submarine, 
174 
and the steamboat, 204 

Galileo, 367-371 
Galvanni, Luigi, 25, 251 
Gasoline engine, 214 

on submarine, 182 
Gas engine, 212 

development, 225 

four-cycle, 215, 218 



Gas ignition, 222 
two-cycle, 215 
Gas explosion, 230 
Gas lighting, 303 
General Electric Company, 303 
Giffard, Henri, 139 
Gisbome, F. N., and Atlantic Cable, 

35 
Gnome engine, 150 
Goldsmith, Alfred N., 131 
Goldschmidt, Dr. Hans, 317 
Governor, Watt's, 199 
Graham- White, Claude, 154 
Gramme-Ring armature, 287 
Gravity, center of, 162 
Gray, Elisha, 50, 51 
Gray, Stephen, 245 
Great Eastern, 37 
Gunpowder, 327 
Guncotton, 334 
Gyroscopic action, not old, i 

of earth, 5 
Gyroscope, and the steerable tor- 
pedo, 21 

as aeroplane stabilizer, 18 

as ship stabilizer, 19 

experiments with the, 21 

explanation of, 13 

from bicycle wheel, 3 

not a puzzle, 2 

precession of the, 4 
Gyro-compass, 6 

action of, 6, 7 

comparison with magnetic, 8 

Haber, 331 

Halley, Edmund, 371 
Handley-Page, 153 
Harvesting implements, 233 



382 



Index 



Haynes, Elwood, and the automo- 
bile, 227 

Heating effects of the electric 
current, 257, 258 

Heaviside, A. W., 76 

Hehnholtz, 41, 143 

Henry, Prof. Joseph, 28, 45 

Hertz, Heinrich, 76, 79 

Hertzian waves, 78, 79 

Herschel, 371 

Holland, John P., 176 

Hubbard, Gardiner G., 42, 45 

Hubbard, Mable, 42 

Hudson-Fulton Centenary, 149 



Latham, Hubert, 149 

Lenoir, J. J. E., and the gas engine, 

213 
Levassor and the automobile, 

227 
LeVerrier, 372 
Leyden jar, 79, 97 
Limelight, 311 
Loading coil, 57 
Locomotive, 206 

built by Peter Cooper, 208 

John Bull, 208 
Lodge, Sir Oliver, 79 
Love joy, 329 



Ignition, gas engine, 223 
Illumination, artificial, 299 
Induced currents, 277 
Induction coil, 93, 279 
Inductance, 98, 105, 107 
Inertia, meaning, 2 
Inventor Supreme, 374 
Iron, cast, 351 

pig, 351 
story of, 348 

Jablochkoff candle, 300 
Jackson, Dr. Charles T., 27, 30 
John Bull Locomotive, 208 

Kelvin, Lord, 36 
Key, telegraph, 120 
Kirchoff, 372 
Kite, 143, 156 
Kitty Hawk, 146 

Lake, Simon, 176 
Langley, Prof. S. P., 144 
Langen and the gas engine, 213 
Laplace, 371 



Magneto, 224 
Marconi, Gugliehno, 72 

and his work, 81 

and transatlantic wireless, 87 
Maxim, Sir Hiram, 144 
McCormick, Cyrus, 234 
Microphone, 64 
Moissan, Prof. Henri, 311 
Mongolfier brothers, 136 
Monorail car, 10 

and gyroscopic action, 15 

and problem of, the curve, 12, 

17 

and transportation, 11 

model of, 1 2 

problem of the, 1 1 
Morse, Samuel F. B., 27 

and the Atlantic Cable, 35 

and wireless, 72 

early experiences, 28 

final success, 30, 31 
Motor, gnome, 150 

electric, 288 

a simple, 290 

Liberty, 153 



Index 



383 



Nebular Hypothesis, 371 
Newcomb, Simon, 147, 372 
Newcomen engine, 195 
Newton, Sir Isaac, 371 
Niagara, power plant, 293 

warship, 36, 37 
Nickel plating, 263 
Nitrates, 327 
Nitric acid, 327 

from the air, 329-332 
Nitrocellulose, 334 
Nitrogen fixation, 328 
Nitroglycerin, 332 
Nobel, Alfred, 333 
Nordenfelt, Thorsten, 175 

Oersted, Hans Christian, 25, 26, 265 
Open Hearth Process, 357 
Oscillation of electrical discharge, 98 
Oscillation helix, 121 
Oscillion Bulb, 127 
Ostwald, 331 

Otto and the gas engine, 213 

Oxy-acetylene welding, 315 

hydrogen blowpipe, 310 

Pannard and the automobile, 227 
Perkin, Sir William, 337 
Periscope, 184 

simple, 191 
Picric acid, 334 
Poldhu station, 86 
Popoff, Professor A., 8i 
Potentiometer, 113 
Poulsen, 126 
Power plants, 292 

waste, 295 
Preece, Sir William, 76, 85 
Pressure, air, 136, 158, 167 

center of, 158, 162 



Pressure, electrical, 253 
Ptolemy, 369 
Puddling furnace, 352 
Pupin, Dr. Michael I., 57 

Railroad development, 208 

Reaper, first, 234 

Receivers, wireless, 123 

Receiver, telephone, 63 

Resonance, electrical, 105 

Rocket, 207 

Rozier and first balloon ascension, 

137 
Ryan, John D., 153 

Sanders, Georgie, 42 
Sanders, Thomas, 42, 45 
Santos-Dumont, 139 
Selden, George B., and the auto- 
mobile, 227 
Siemens and the dynamo, 286 
Simon, 124 

Smith, Hon. Francis O. J., 30 
Spark coil, 118 

gap, 119 
Speaking arc, 124, 125, 131 
Sperry, Elmer A., 6, 9, 21 
Sperry, Lawrence, 18 
Stanley brothers and the automo- 
bile, 227 
Steam Age, story of, 194 
Steam, boat, 204 

engine, 202 

superheated, 200 

turbine, 205 
Steams, J. B., 33 
Steel, industry, in the United States, 

359 
in the war, 349 
manufacture of, 353 



384 



Index 



Steel, story of, 348 
Stephenson, George, 207 
Storage. battery, 272 

Edison, 274 

lead, 273 

on the submarine, 182 

uses of, 274 
Stringfellow, 144 
Sturgeon and the electro-magnet, 

26, 266 
Submarine, 173 

antidotes for, 188 

construction and equipment of, 
181 

experiments on, 190 

explanation of, 177 

Holland, 180 

in the Civil War, 175 

Lake, 176 
Sully, packet-ship, 27 

Telegraph, 25 

appropriation for, 30 
a "scientific toy," 29 
explanation of, 31, 32 
first message, 31 
musical, 41-45 
Wheatstone's, 26 
Telegraphy, duplex, 33 
wireless, 72 

amateur, 90 

in war time, 89 

later development of, 88 

the future of, 90 

transatlantic, 87 
Telephone, 40 
a home-made, 70 
and Dom Pedro, 48 
a simple, 68 
at the Centennial, 47 



Telephone, central, 67 

first exchange, 50 

in war, 59, 60 

line, 66 

organization and development, 
52-56 

patented, 47 

receiver, 63 

the first demonstration, 49 

the first message, 46 

theory of, 61 

transcontinental, 56, 57 

transmitter, 64 
Telephone, wireless, 124, 125 

long distance, 130 

simple, 132 
Telescope, explanation of, 372 

first, 368 

a great, 373 
Tennyson's prophecy of aerial 

achievement, 155 
Thermit welding, 317 
Thomson, Prof. William, 36 
Torpedo, 186 

Whitehead, 175, 186 
Tractor, farm, 228 
Transformer, loi, 279 
Transmitter, Blake's, 65 

telephone, 64 
Trinitrotoluol, T. N. T., 334 
Trowbridge, Professor, 74, 75 
Tuning, 108 

coil, 122 

sharp, no 

U-Boats, 181, 188 

Vail, Alfred, 29 

Vail, Theodore N., 51, 55, 561 
130 



Index 



38s 



Van Drebble, 173 
Vibrations, sympathetic, 41, 44 
Vibrating reeds, 43 
Visible speech, 42, 44 
Volta, Alexander, 25, 251 
von Baeyer, Adolph, 337 
von Guericke, Otto, 224 
von Welsbach, Dr. Carl, 303 

Watson, Thomas A., 45 

opening transcontinental service, 
57 
Watt, James, 195, 197 
Waves, broad, no 

loose, no 
Welding, electric, 314 

oxy-acetylene, 315 

thermit, 317 
Western Electric Company, 55 
Western Union, 50, 51 
Wheatstone, Sir Charles, 26, 41 



Wilde, Dr. Henry, 284 
Wireless telegraph, 72-91 

aerials, 103, 116 

a simple set of, 116 

condenser, 120 

detector, 121 

experiments, 115 

operations of, 93 

receiving apparatus, in 

sending and receiving, 1 14 

spark coil, 118 

spark gap, 119 

telephone, 124, 125 

transmitting set, in 

tuning coil, 122 
Wright, OrviUe, 145, 148, 149 

warping device, 148 

Wilber, 145, 148, 149 

Zede, Gustave, 175 
Zeppelin, the, 140, 141 



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